If you use a charcoal grill, as opposed to a gas or electric one, you know that the optimum moment for grilling depends upon a lot of factors, not the least of which is the weather or the way the fire was built. If you deal with those kinds of vagaries, this is the perfect recipe to make. The salmon can be marinated and grilled ahead; it can even be refrigerated several hours in advance of serving. All you really have to factor in is the half-hour that is needed for it to stand at room temperature to come to full flavor.
2 tablespoons fennel seeds, toasted
½ cup extra-virgin olive oil
¼ cup freshly squeezed orange juice (2 small oranges)
6 salmon fillets (1 ½ to 2 inches wide), about 6 ounces each (skin left on)
Crush the toasted fennel seeds in a mortar with a pestle, or in a spice grinder. Transfer to a wide, shallow ceramic or glass dish, such as a pie plate, add the olive oil and orange juice, and stir to combine.
Add the salmon fillets to the marinade, turning to coat them all over, and let stand, covered at room temperature for 1 hour.
Place the grill rack 1 to 2 inches from the coals. Preheat the grill until the coals are white.
Remove the salmon from the marinade, letting the excess drip off, and discard the marinade. Place the fillets, skin side down, on the grill and cook for 3 to 4 minutes. Turn carefully, with long-handled spring tongs if you have them, and grill for 3 to 4 minutes more, or until the flesh flakes easily when tested with the tongs or a fork. (You may need to move the fillets slightly toward the side where the heat is less intense, to prevent burning.) Transfer the fillets to a platter and let cool. (The fillets can also be cooked in a grill pan top of the stove; place skin side down, in a dry pan, cook 4 minutes, turn, and cook another 4 minutes.)
When the salmon is cool enough to handle, remove the skin. Arrange the fillets on a platter and serve within 1 hour of cooking.