There are a few ways to travel at high speed on the ground in Wind Waker.
To perform a Moblin Slide, first freeze a moblin, and wait until it unfreezes. As soon as it unfreezes, pick him up and you will slide at very high speed. This is hard to control, but can allow you to cross large gaps, in Hyrule Field for exemple.
Note: This was patched in the HD version.
Stun a Magtail and wait until it unmorphs. Stand close to it. As soon as it unmorphs you will take damage, and during your damage invulnerability, pick him up and you will slide at high speed, just like a Moblin Slide.
This sliding glitch works differently than the others listed above. To perform a bokoblin slide, you must first disarm a bokoblin. Wait until the bokoblin runs to get his weapon back and stand next to him. The bokoblin will usually perform a ripost attack as soon as he gets his weapon back, and that will make Link slide at high speed. Note that the furthest the bokoblin has to run to get his weapon back, the fastest your slide will be.