Touch is a first class-citizen in Windows Store applications, so no special accommodations are needed. I would recommend you test on a touch device though before deploying, it's a different way of interacting, and even though the simulator does a decent job of handling the mechanics, it will "feel" different to a user - especially if you're leveraging pinch-zoom, swipe and other gestures.
On another note... is this app intended for a kiosk-type application? If so, keep in mind with Windows 8/RT, you won't be able to easily prevent the users from swiping to the charms, navigating to other programs, etc. You may want/need to take a look at Windows 8 Embedded depending on the specific deployment requirements.