For It's Rude To Point, our team's "only one" was interpreted as "only one finger". With one interactive finger, you would interact with on-screen objects by either grabbing or flicking them.
We actually stuck very closely to this concept, but instead of just making it a point-and-click sandbox game, we decided to spin it into a series of short action minigames that would all involve the finger in some manner - very similar to WarioWare or Dumb Ways To Die.
It'd be much appreciated if you could give It's Rude To Point a try, and possibly a rating too! It's WebGL-based, so you don't have to download anything to be able to play it (aside from the Unity Web Player plugin).