How to Make It
Stir the rice into a medium pot of boiling, salted water and cook until just done, about 10 minutes. Drain. Rinse with cold water and drain thoroughly.
In a large glass or stainless-steel bowl, combine the lime juice, fish sauce, 1 tablespoon of the oil, the sugar, and cayenne. Let sit for about 5 minutes. Stir in the rice, cucumber, carrots, scallions, and cilantro.
Heat the broiler. Oil a broiler pan or baking sheet. Coat the salmon with the remaining 1 tablespoon oil and sprinkle with the salt and pepper. Put the salmon on the pan. Broil until just barely done (the fish should still be translucent in the center), about 5 minutes for a 1-inch-thick fillet. Put the rice salad on plates and top with the salmon.
Asian fish sauce is available at Asian markets and many supermarkets.