Search the following locations to find the coins.

Coin 1: Located in the Dragons mouth. To get it, go to where the money shot is found and walk on the dragon until you make it to the head. Press A.
Coin 2: In the room where the meat grinder is located, go to the elevator. Kill all the guards on it. Defeat Yuu Fung to get the next coin.
Coin 3: Stay on the roof and look for the grapple point somewhere on the corners. Slide up the grapple and kill all the enemies at the bar. The bar produces a constant supply of meat buns so you can distract the enemies while you fight. Kill all enemies and grab the coin before it gets to the other side.