I'm looking for games I can play comfortably on my tablet, which boils down to games that mostly rely on using the mouse.
I thought I would try playing Eye of the Beholder, but the touchscreen on my tablet doesn't seem to work properly as a mouse click. I sometimes get a cursor appearing in the corner, but not where I'm touching.
I would assume this is some kind of issue with DOS Box interfacing with my touchscreen. Are there any settings I can try to adjust to get the touchscreen to respond properly with the game?

Dosbox is wonky for touchscreen. I assume you're on something other than a windows tablet.

and yes it is ironic when you consider that tablets should be a great device for playing those sorts of games.

As far I know, touchscreen support on DOSBox is still a work in progress and not very important one at that.

I've been playing on a tablet for the past 2 years and is great, came to find that many games have native touch screen support.

https://store.steampowered.com/curator/7473504-Touchscreen-Games/
https://store.steampowered.com/curator/6857883-Touch-friendly-games/

Used those 2 lists as a resource. I can recomend some games I play on a Atom z8350 powered tablet:

Into the Breach freaking great game, one of my favorites ever! Last update suposedly introduced touch controls but already had partial support for over a year. It plays perfectly!

Steam World Heist Awsome game overall and the music is superb.

Fell Seal: Arbiter's Mark Quite good strategy game, like Into the Breach and SteamWorld Heist can be played with touch, mouse, keyboard or controller at any time.

Grid Autosport this game is not available on GOG but if you want to try it, is available from Humble for 1€ at the moment (Steam key). I really enjoy the game, unlike previous Grid, Dirt 3 and 4 but touch controls are not the best way to play it. Also the game looks good but is heavy, although not unplayble on minimum settings, unlike any other Grid or Dirt game that stutter every few seconds (thanks to Intel support).

Shadowrun Returns didn't play a lot because its quite heavy for my modest CPU but not unplayable if you can manage a couple of frame drops here and there.

Trine 2 great controls and acceptable performance.

plants vs zombies performance seems a bit odd but touch is perfect, the game is good and fun too.

X-com has touch controls but never tried, it runs quite slow and a potential workaround is to re-encode all the game videos.

PPSSPP the PSP emulator have very good touch controls. Recent versions of Retroarch may have implemented touch controls already (the Android version has them for years).

As a recomendation, a controller is a good company to the tablet, as it open up a lot of possibilities and a fast memory card a must. I use a Sandisk A1 rated 128Gb SD card for storing games.
If you have something like a Surface pro 2 and up, performance is not a big deal but on a Atom/Celeron, game tweaks are a must.

Actually this is a Surface. I did come across those lists, but it is still hard to find good games that I want to play, you know?
Plus I am having problems with some games taking touching the screen as if it were hovering instead of clicking, so I have to click twice to do anything. It would probably work better with the pen, but right now my pen isn't working. That's a different issue though.

You may want to check your settings. Windows has a setting to be able to single click any icon, let me check...

Edit: On Windows 8.1 is located on folder option, on control panel. You can also open folder Explorer, view and options. Sorry if there is any translation error on my part because my OS is no in English.
If you are using Windows 10, good luck but you can find the setting the same way, using the Explorer -> View -> options.