Basically she does a handstand, does the splits upside down, and spins like helicopter blades from one side of the game screen to the other in midair close to the ground. If the opponent is in the way and not blocking, they get hit several times and suffer damage!
In another game, Capcom gave her a similar move that caused her to rise up in the air at an angle as she spun around to stop midair attacks by opponents.
P.S. In one of the later games in the Street Fighter franchise, Capcom gave her a kick-based 'Raging Demon' attack (see Akuma) that looks cool on the screen (like a ukyo-e drawing) but I don't know what it's called in Japanese (or English).