Ribs With Orange and Pickled Onion

Toast star anise, coriander seeds, cumin seeds, mustard seeds, and cloves in a dry small skillet over medium heat, tossing occasionally, until very fragrant and just beginning to darken, about 5 minutes. Transfer to a plate; let cool. Finely grind in spice mill or with mortar and pestle; transfer to a bowl. Finely grind chiles de árbol, guajillo chiles, and half of sesame seeds. Add to ground spices along with sumac, cocoa powder, cinnamon, allspice, coffee, and remaining sesame seeds; mix well.