12 ounces72% cacao dark chocolate, broken into pieces
Line baking sheet with aluminum foil.
Toast seeds in heavy-bottomed skillet over medium heat. Cook until seeds hiss and pop, becoming fragrant, about 5 minutes. Combine with cinnamon, chili and cayenne and stir. Sprinkle with salt. Allow to cool.
Add half of chocolate to double boiler over medium heat. Melt, stirring occasionally, about 6 minutes. Add remaining chocolate. Stir until melted. Add toasted seeds and stir. Set some aside to sprinkle on top.
Pour chocolate onto baking sheet in even layer of about 8x10 inches. Sprinkle with remaining seeds. Refrigerate 30 minutes. Break into pieces.