Based on the (user-level) simplicity of the interface, I think you could map it to the numpad.
A prototype exploration game for ProcJam. You wander around a generated level. And that IS what this game is...but it will definitely be more complicated later!
CONTROLS: CLICK STUFF! Note that if you click the upper part of the playfield, you'll go upward; the right part, you'll go right, etc.. Clicking the corners is supposed to have other effects. Clicking the middle should do nothing.
Update Nov. 30: Should work much better on mobile screens! I can now play it on my phone, so that's progress.