1. Preheat oven to 300ºF. Line a large, rimmed baking sheet with parchment. Combine popcorn and peanuts on baking sheet.
2. Mix brown sugar, butter and corn syrup in a small pan. Bring to a boil over medium heat. Boil without stirring for 4 minutes. Remove from heat; stir in baking soda. Quickly pour caramel over popcorn and peanuts; toss with 2 rubber spatulas or spoons. Bake for 20 minutes, stirring twice.
3. Place chocolate chips in a small microwave-safe bowl. Microwave on medium heat in 10-second bursts, stirring in between, until almost melted, 40 to 50 seconds total. Stir in cayenne and cinnamon. Transfer to a ziplock bag, cut a small hole in a corner and drizzle chocolate over popcorn. Let stand until set, 3 to 4 hours. Break into pieces and serve.