When you go to fullscreen, the game asks if you'd like to turn on keyboard controls, which sounds promising, but I don't know what the keyboard controls are. I had a search here and the wiki, and couldn't find anything.
As far as I can tell, it's just a part of Flash's fullscreen code. The "keyboard controls" may have nothing to do with controls internal to Card Hunter. Developer replies in this thread suggest that they are limited in how they use Flash's system here.
That has nothing to do with us. We don't have a lot of keyboard controls, although I think spacebar still zooms (like right-click).