I can't stand playing games on Android I think the only game that really works with the touch screen is Angry Birds. There's no way I could enjoy controlling through an emulator when I have the real thing.
Any American Laser Games light gun shooter would be fine played this way, touch to shoot would work well.
I would think in those games, accuracy would be impossible on such a small screen. Even a standard television set is a bit too small for what most of ALG's light gun games were designed for. Some of the randomly generated levels of Space Pirates make me absolutely want to pull my hair out because consistently hitting certain targets is all but impossible, and I've completely given up on beating Mad Dog II.