For this simple salmon dish, we coat fillets with sesame seeds, which form a crisp, nutty-tasting crust as the fish cooks. A tangy, savory, pleasantly pungent Cambodian black pepper and lime sauce called tuk meric is served on the side to complement the richness of the salmon. The sauce traditionally is paired with the beef stir-fry known as loc lac, but we find it brightens up a host of other foods, including seafood. Be sure to grind the peppercorns coarsely, not finely, for the sauce using a spice mill or a mortar and pestle.