Upon cancelling a dash, Link will slide forward with some momentum. This momentum is maintained upon leaving the ground and can be used to cross short gaps or glide off of cliffs.
Position Link at a key spot to perform the dash cancel, then begin the dash. Once you start the windup to the dash, hold the circle pad in the opposite direction. Keep it held until after the dash cancel occurs. This will guarantee that the cancel occurs at the same moment every time. Be careful not to hold in the opposite direction at the same time as starting the windup, or Link will turn around while winding up.
Perform a dash slide while carrying a Cucco off of a ledge to combine the speed of the dash cancel momentum with the Cucco flight. Note that you will need to return the circle pad to neutral or forward as soon as you leave the cliff, or you'll lose speed on the flight.