Step 1Oil a grill rack or grill pan. Heat the grill to medium-high or the pan over medium-high heat.
Step 2Meanwhile, place the cumin, coriander and cinnamon in a small skillet. Toast over medium heat until fragrant, shaking the skillet often, about 2 minutes. Remove the spices from the heat and let cool 1 minute. Transfer them to a spice grinder and pulverize. Place the mixture in a small bowl; mix in the salt and cayenne pepper.
Step 3Pat 1 teaspoon of the spice mixture on the flesh side of each filet, rubbing so it adheres, and rub each filet with 1 teaspoon of olive oil. You will have about 1 1/2 tablespoons of the spice mixture left over. Store it in a tightly closed jar.
Step 4Grill the salmon, flesh side down, for 6 minutes. Turn the filets over and grill just until cooked through, 5 to 8 minutes, depending on the thickness. Serve immediately.