Skimming is a specialized use of the One Power. It is the simplest form of Traveling, but while the ability to Travel is considered a Talent, the ability to Skimming is not and all channelers can use it when the required strength is provided.
Skimming is performed by opening a gateway to a pitch dark area where the user creates a platform, gets on it, and moves in any direction he or she wishes. If anyone falls off that platform, that person will fall forever and die of starvation or sheer terror, unless he or she can channel.
As Skimming is a more indirect version of Traveling, the channeler does not need to know his or her surroundings and destination quite as thoroughly. Some familiarity with the area is still required, but it can usually be gained with only about a half hour of examination. If the destination is completely unfamiliar, the channeler can still use skimming, but must estimate the distance and direction and will not be able to open a gateway in any specific place.
Skimming was first rediscovered in the Third Age by Rand al'Thor. It is mentioned in A Crown of Swords that unless two people attempt to skim with exactly the same start and destination, they will never see each other while skimming. This seems like it would make Rand encountering Asmodean while skimming to Rhuidean very unlikely, but he is Ta'veren after all.
Among female channelers, Egwene al'Vere holds the credit after discovering Traveling and then being taught the alteration by Moghedien, as knowledge of Skimming's existence hadn't survived to the Third Age.
The name may have come from the Age of Legends or Asmodean.