Level select:
Highlight the "Exit" option on the configuration screen and press L(2), R(3), L(3).

Refill red crystal:
Pause game play and press Up, X, Right, A, Down, B, Left, Y. This will restore your character's power.

Refill green crystal:
Execute a spinning back kick (Away + Y), pause game play, and press Up, X, Right, A, Down, B, Left, Y, Start. This will restore your character's health.