I ran into a similar problem with a Customer's netbook earlier this year when he tried to upgrade to W10 from W8.1. He had the 32GB SSD drive same size as yours. He had it for 3 or 4 years, so relatively new. When I got it to my workbench from the Customer I noticed while testing it, the capacity of the SSD drive was only like 24GB instead of the 29GB or 30GB that should be there after the overhead of drive formatting via NTFS reduces the total useable capacity of the drive (32GB).
I solved this problem by doing 3 things.
#1: I backed up all his data to external media and then used windows Disk Management tool to Extend his Volume to the maximum capacity of the drive around 29GB or so. This picked up about 5GB; but the W10 upgrade needs at least 9.3GB (or it did earlier this year) in order to work. Customer had his SSD drive about 98% full; so he had like 22.5GB out of 24GB used; no space to do anything.
#2: I then looked at his data in his Library folders and saw he had several GB of data including Browsing History and Cookies just sitting there taking up space; I cleared all this off to external media backup. Regained some more space.
#3: Went into his Programs and Features applet and saw he had like 60 or 70 programs installed including stuff like MS Office 2013 and some photo editing software. He had several toolbars *most of which contain viruses* in there and a bunch of freeware, over two-thirds of which he was no longer using. I then pruned off all of those unused or unneeded programs and picked up a few more GB of space. After doing all this, I got his used space down about 10GB to <19GB and I was then able to run the W10 upgrade and it worked perfectly!
The moral of this story is that your Hindsight is 20/20 about purchasing such a small hard drive; this is not a size that will allow your laptop to really store much of anything such as documents, pictures, videos/movies, music, etc. It's meant to be what we call an "Internet Applicance" we call it in the biz; which was an idea that came out with the "Earth Station" which came out in the 80s. It was similar to the All-in-One computers now prevalent from Dell and HP. It was a keyboard-computer, the computer guts were all inside of the keyboard and you just needed to plug in an external monitor or TV and a mouse to it and off you go. It disappeared shortly due to failing sales, but the idea was sound. Now Intel and Lenovo have TV-Computer Sticks for about $100 that do the same sort of thing in the size of a pack of gum. Sorry to divert there. Just some perspective on what the laptop guys are thinking when they give you a hard drive size that hasn't come on laptops for 15-20 years.
I would go into your Programs and Features and see if you have more than about 5 programs installed that aren't part of windows, and if you have more than that you'll need to remove all of them to get enough space to do anything with a laptop drive that small. Also, you'll need to pare down all your library folders as I mentioned in my little repair anecdote above as well. According to the ASUS site, they give you 500GB or 1/2TB of free Cloud storage with your laptop, you can offload all your non-essential library data to that location. Or use the free Dropbox or Microsoft OneDrive (included with W10). Even the laptop makers realize just how small 32GB is nowadays, and that's why they give you free Cloud Storage, because you have pretty much no room to store anything on that laptop drive AS YOU HAVE OBSERVED!

And if you are trying to do an OS update such as one of the 7 AU updates released since Aug. 2nd; pretty much no Bueno unless you have just about nothing saved there. Remember that new Cell. phones now come with more memory than you have with that laptop (my new LG-Android came with 64GB and my wife's iPhone6Splus came with 128GB). Of course Cell. phone apps are WAY smaller than PC/Laptop apps because they have to be; but I have like 40 or more apps installed on my phone and still have room to spare. I think you're getting the picture now, and the lightbulb has come on that's floating over your head now.
Another route to consider and you can't wrap your head around having no ability to save anything or add programs to the factory build on your laptop that ASUS gave you, why not consider replacing the SSD drive in your laptop to something reasonable such as a 250GB or larger SSD drive. You can use Macrium, Acronis, or EASETodo image backup software to make an image of the W10 on your current 32GB drive, throw in a larger capacity SSD and then restore the image onto the new SSD drive and you'll have oodles of room to spare. New SSD drives such as the Kingston 240GB SSD are only $79.99 US at newegg:
Kingston SSDNow V300 Series 2.5" 240GB SATA III Internal Solid State Drive (SSD) SV300S37A/240G-Newegg.com.
That's certainly cheaper than junking that new laptop, as it's pretty much unusable for most traditional computing needs. If you've never swapped out a drive before in a laptop, consider taking it to your local Computer Pro or repair shop; they can do it for $140-$180 US or so, and that includes the new drive.
EDIT: We've only tested 3 brands of SSD drives to work with W10 computers; Kingston, Intel, and Crucial. Keep this in mind when purchasing your new SSD drive!
Hope that helps.
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