mix the rice and 2 1/3 cups water in a medium skillet. bring to a boil. reduce heat to low and simmer, covered, for 10 minutes. slice the salmon on a diagonal into four 3/4 inch thick pieces. season with 1/4 tspn salt and 1/4 tspn pepper. place on top of the partially cooked rice. cover and cook for 7 minutes. scatter the peas over the salmon and rice. cover and cook until rice and peas are tender and the salmon is opaque and beginning to flake, 3 to 5 minutes. mix the soy sauce, scallions, vinegar, ginger and sugar in a small bowl. spoon the sauce over the salmon, rice and peas and serve.