Also known as Quick-Hopping or Ledge Jumping.
By hitting Jump again right after Samus is grabbing the ledge, you can often forgo the animation of Samus grabbing the ledge and pulling herself up. This is similar to the way it is executed in Super Metroid; you are essentially spin jumping off of the edge of the platform's collision. If perfected, it makes it far easier to navigate multiple platforms. The reason you want to do this is that it negates the "mantle" animation of Samus mounting a ledge for a hanging and pulling up sequence. You should aim to Ledge Jump whenever navigating platforms to save time.
Normally you can't perform the same way as on land without the gravity suit. Instead, you should grab the ledge, jump to the reverse direction and immediately flick back the desire direction.