Heat oven to 350 degrees. Toast almonds for 15 minutes on a baking sheet. Line two baking pans with parchment paper; set aside.
In a medium saucepan, combine granulated sugar, 1/4 cup water, toasted almonds, and cinnamon. Cook, stirring constantly, until sugar becomes golden and granular and almonds are completely coated and separated. Pour nuts onto prepared pans. Chill in freezer, about 15 minutes.
Meanwhile, place chocolate in a medium bowl; place bowl over simmering water until melted. Transfer half the chilled almonds to a large bowl, and pour half the melted chocolate over nuts. Stir until nuts are thoroughly coated. Transfer nuts onto prepared baking pan. Using two forks, separate nuts so none stick together. Return almonds to refrigerator until chocolate has set, about 20 minutes. Repeat with remaining almonds.
Place cocoa powder and confectioners' sugar into two separate bowls. Toss half the nuts in cocoa and half in sugar, and gently tap off any excess powder. Store separately in airtight containers for up to 1 month.