Heat the coconut milk to a simmer, either in a saucepan or the microwave.

Put the chocolate and coconut oil in a large bowl and pour the hot milk in. Stir gently, until chocolate is melted, and mixture is smooth. Add the peppermint extract, and stir until combined. 

Cover the mixture and refrigerate until firm, 3-4 hours, or overnight. 

When ready to make the truffles, pour some cocoa powder in a small bowl. Remove chocolate mixture from fridge, and scoop into 36 1-inch balls using either a melon baller or cookie scoop. Form into balls and roll in the cocoa powder. Store in an airtight container in the fridge until ready to serve.