Christian Heilmann has a neat article and video about using the Leap motion for accessibility gestures.
In essence, this means:
Swiping your finger right will scroll the page down, left will scroll up. The speed of the swipe defines the amount of pixels scrolled
Making a clockwise circular gesture will jump to the next link, making a counter-clockwise one to the previous link
A tap gesture in the air will activate the link
via Playing with Leapmotion for accessibility | Christian Heilmann.