Gecko Skinning is a Fallout 2 perk.
This is a special perk, so it cannot be taken at new levels like other Perks. It can be learned only from Smiley the trapper after rescuing him from the toxic caves not far from Klamath.
It allows to properly skin geckos (excluding fire geckos) for gecko pelts and golden gecko pelts, they can then be sold for profit.
This ability is made standard in Fallout: New Vegas.