Mix the rice and 2 ⅓ 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 ¾ inch thick pieces. Season with ¼ teaspoon salt and ¼ teaspoon pepper. Place on top of the partially cooked rice. Cover and cook 7 minutes.
Scatter the peas over the salmon and rice. Cover and cook until the 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 brown sugar in a small bowl. Spoon the sauce over the salmon, rice and peas and serve.
