1. Place chocolate in a medium bowl. In a small pan, combine cream and chile. Bring just to a boil over medium-low heat. Remove from heat. Stir in vanilla, salt and cayenne. Pour through a fine-mesh strainer over chopped chocolate. Discard chile. Let chocolate and cream stand for 5 minutes. Stir until mixture is smooth.
2. Pour mixture into a 13-by-9-inch baking pan. Refrigerate uncovered until just set, at least 1 hour.
3. Line a baking sheet with parchment. Sift cocoa, chili powder and cinnamon into a small bowl. To form each truffle, scoop up a tablespoon of filling. Roll it into a ball with your hands. Roll ball in cocoa mixture to coat evenly. Place truffles on prepared baking sheet. Serve immediately, or store in an airtight container in the refrigerator for up to a week. Bring to room temperature before serving.