Location: Tancheng City
Petitioner: Lord An
Reward: Martial Arts Thoughts, 5,000 coins
To trigger this side quest you first need to find your way to Tancheng City. It's located to the south of Pingkang City and the general starting area of the game. Head south until you see a waterfall, then cross the nearest bridge and keep going south a ways until you see a settlement on your right. This is Tancheng City.
The petitioner for this quest, Lord An, is standing outside a house in the southwest of Tancheng City. He'll get right to the point when you speak to him: Lord An wants Hides from the animals that live on Mount Greenturnip. Five Hides will do.
You can get Hides from animals as drops throughout Wandering Sword. If you don't happen to have five of them on you, however, you should make the trip to Mount Greenturnip. This outdoor dungeon is located northeast of Tancheng City, and it's stuffed full of animals to hunt that will drop Hides - though you should stick to the White and Grey Wolves. (I don't think I ever saw a Leopard drop a Hide.) If you're tackling this quest early in the game you may want to bring one of the 'mandatory' party members along, such as Mowen, Moqi, or the Girl in Red, as these animals are tough for new players.
Return the Hides to Lord An. In addition to your reward you'll receive an explanation regarding the members of the Beggars' Guild, which you probably didn't expect. Well, there you go. Quest complete.