As soon as you complete The New Kid in Town, you will be able to freely explore South Park. On the north side of the map is the restaurant, City Wok. Head inside and talk to Mr. Kim, who will give you a key to the Tower of Peace, where he wants you to beat up on the Mongolian kids so the Mongolians leave South Park.
As soon as you enter the tower, you'll be thrown into a fight with some of the kids. After, shoot the pulley to make the stairs fall and head to the second floor. There will be more kids to fight here, as well as a Chinpokomon hanging in the cage on the right side. Defeat the kids on the third floor and shoot down the dragon piece hanging up on the right side.
Place the missing piece and then quickly shoot the eyes of both dragons to open the door. At the top of the tower, you will have to fight the Mongolian Horde, which is the boss. Other than its ability to cause Burning and Bleeding with their attacks, it's a pretty typical fight. Once you win, return to Mr. Kim to finish the quest, who will become your friend and give you an item to summon him in normal battles (not bosses and only once per day).
