Zulian Slicer is a one-handed sword that increases the wielder's skinning skill level. The only other weapon that increases skinning is the dagger [Pip's Skinner].
Since paladins cannot equip daggers, paladin skinners must obtain this weapon rather than the dagger Pip's Skinner if they wish to increase their skinning skill beyond using [Skinning]. Hunters, warriors and rogues can dual wield this weapon and Pip's Skinner in order to stack their bonuses together. Combined with the +5 skinning enchant to gloves, this would give a skill bonus of +25, though there are no mobs that require that much skill.