Summary
While performing a regular jump, if your character is against the back wall, hitting Forward Flip will allow the character to jump off the wall.
Off the Wall
All Wall Jumping really affords the character is a little extra boost in height and the ability to alter the direction of their regular Jump if they are jumping straight up or backwards near the wall. The good thing about Wall Jumps is that it is considered a completely separate action from Air Dashes and Double / Triple Jumps, so it does not eat into the allowed amount of those actions.
Strategy Corner
Double Jump and Air Dash same count, Wall Jump exclusive count.