Can I record left and right hands at the same time?

The Left Hand and Right Hand tracks in Pianissimo are named Left Hand and Right Hand as a helpful guide, but you can record whatever you'd like on either track.  Arm either track and press Record, and you can record an entire composition.

If you wish to record each hand separately, it can be helpful to record your left hand on the Left Hand track, and your right hand on the Right Hand track.  However, you can do whatever you wish, as either track will record the entire 88 key range of the piano.