hi,
I'm thinking of buying a tablet for leisure and games that controll well with touch controlled. Grimrock seems like an exellent game that's not to hard on hardware. So that leaves me with the question. Can it also be played with touch screen?

You can enable on-screen GUI for movement (equal to QWE-ASD on keyboard) so that appears to help. Not sure though how you'd have a difference between rightclick and leftclick on the weapons, inventory screens and such.

i tried it on an win8-tablet with intel atom (and intel-graphics). It was no fun.
you need right-mouse-click for weapon-usage, right-mouse is done by holding your finger for a long time (1 or 2 seconds) on a spot - its ok for opening the cage in the beginning, but to slow for a fight.
On-screen-gui for movement is on the wrong side for two hands and no esc-key for menu (save your game...).
last point: it is to hard for my hardware, runs with 5 to 10 fps (not exact, only my feeling), sometimes the touch responds very late.
for me, its not playable on my tablet.

some tips for tablet games:
Heroes of might and magic 4 and 5 (never tried 3 or older on my tab)
battle isle 3
braveland
triple town

IIRC, there is a port of Grimrock 1 for iPad. I haven't played it however and I don't know if they also plan a port for Grimrock 2.

No, they are currently back to working on it (ios grimrock 1) now that GRII is released. They signed on a 3rd party developer to assist with the porting and are currently working on the interface now.

You can see their thoughts in a post on their website from back in August when they reversed their decision and decided to enlist 3rd party help to get it done. And you can hear it straight from Juho Salila's mouth in a recent interview post GR2's release that he's working on the ios interface.

Best way to handle rightclicking would be 2nd touch imho.

As in you would just put your left thumb on the screen and hold, and then tap with the right thumb (or whatever finger) where you wanna "right" click.