Preheat oven to 450 degrees F (230 degrees C). Lightly grease a shallow 9x13 baking dish. Combine the coriander seed, brown sugar, and lemon-pepper seasoning in a small bowl, and blend well. Place the salmon fillet skin side down in the prepared baking dish. Brush top and sides of fillet with the butter. Sprinkle the fish evenly with the coriander spice mixture, gently pressing it into the fish. Stir the mango, cilantro, and lemon peel into the rice. Spoon the rice mixture around the fish in the baking dish. Bake in preheated oven until fish flakes easily when tested with a fork, 4 to 6 minutes per 1/2 inch thickness. Cut the fish into 4 pieces. Divide rice between 4 serving plates and place the fish on top.