In a medium skillet, combine the fennel and coriander seeds with the peppercorns. Cook over moderate heat, shaking the skillet a few times, until the fennel seeds turn light brown, about 2 minutes. Add the crushed red pepper and toss until fragrant, about 20 seconds. Transfer to a plate to cool completely. Put the toasted spices in a spice grinder and grind to a powder. Transfer to a bowl and stir in the chile powder, salt and cinnamon.
The spice rub can be stored in a jar for up to 1 month.