Line baking sheets withparchment paper. Beat confectioners’ sugar, butter, cream, peppermint extract, vanilla extract, and salt with an electric mixer on low speed until smooth, 1 to 2 minutes. Roll into 30 balls. Place on prepared baking sheets and flatten into 1/4-inch-thick disks using a greased piece of wax paper. Cover and freeze 30 minutes. Microwave chocolate and coconut oil in a bowl 30 seconds; stir. Continue to microwave and stir in 10-second intervals until melted. Place 1 chilled peppermint disk on tines of a fork and dip into melted chocolate, tapping off excess; return to baking sheet. Repeat with remaining peppermint disks. Sprinkle tops with crushed peppermints. Chill until set, 15 to 20 minutes. Store, refrigerated, in an airtight container up to 1 week.