For the crusts, preheat oven to 350 degrees F.
Pulse coconut, sugar, flour, cookie crumbs, cocoa and salt in a food processor (just to grind the coconut a bit). Add butter and pulse until crumbly. Add yolks and vanilla and pulse until dough just starts to come together.
Spoon a tablespoonful of dough into each cup of an ungreased mini-muffin tin. Press dough firmly to pack and bake for 15 minutes. Allow to cool while preparing filling.
Beat egg whites until foamy, then slowly add in 2 ½ cups icing sugar on low speed. Add peppermint extract and increase speed to high. Beat for 3 minutes, until filling has body, but is still soft. Adjust with additional icing sugar, if needed.
Spoon or pipe a tablespoonful of filling into cooled shells and let set in an airtight container for at least 2 hours before serving.