For the mint dipping sauce: Place the mint leaves, sugar, salt, coconut milk, lime zest, and lime juice in a blender and puree until smooth. Transfer the mixture to a bowl and place in refrigerator. For the coconut shake and bake: Preheat the oven to 375 degrees F and line a baking tray with parchment paper. Put the chicken in a bowl, drizzle with vegetable oil and toss to coat. Season the chicken with garlic powder and cayenne pepper, if using. Toss to coat evenly. Put the shredded coconut and panko bread crumbs in a resealable bag. In batches, add the chicken pieces to the bag. Close the bag and shake to distribute the coconut and panko bread crumbs evenly. Remove the chicken pieces from the bag and place on the prepared baking tray. Repeat the coating process in batches with the remaining chicken. Bake the chicken in the oven until the chicken is golden brown and cooked through, approximately 45 minutes. Serve with the Mint Dipping Sauce.