Instructions
Go to the local shop at the Pirate Outpost. The outpost is to the west of the Golden Harbor.
Sell your grain and buy spice.
Jump to the top of the skull in this area. Hop over the enemies to get to the top.
Jump to the top of the mast. Push against the barrel to slide it into the water.
Hop into the water. Push against the fallen barrel until it is under the skull's golden tooth.
Go back to the cannon on the left. Click on the cannon to shoot the barrel and get the tooth out of the way.