How do I overlay an animation over the home screen?

I saw an app that allows you, once you run it, to blow little holes all over your home screen, even with Live Wallpaper continuing to run in the background.  What I want to do is similar in that I want to be able to interact on a layer OVER the home screen.  Basically, I want to create an app with a transparent background that allows you to see through to the mobile desktop underneath.

I know this is possible, but can Air for Android do this?  Is this a SurfaceView method?  SurfaceHolder?  If anybody could help me, I'd be super super grateful!  This has me completely stumped and the lack of information in other forums leads me to believe this might not be possible.