Finely dice pepper trimmings into confetti-like pieces for a stylish garnish; set aside. In glass measuring pitcher, combine soy sauce, onions, ginger and sugar, stirring to dissolve sugar. Alternate shark, peppers and mushrooms on skewers. Thin cubes of shark can be folded in half, and then speared. Place skewers in glass or plastic pan. Pour marinade over skewers, reserving 1/3 cup. Marinate skewers in refrigerator for 30-60 minutes once or twice.
While skewers are marinating, prepare grill or preheat broiler. Remove skewers from marinade, broil or grill 6-10 minutes, turning once or twice to brown evenly. Baste, if necessary, with reserved marinade. If desired remaining marinade may be simmered for 5 minutes (or heated in microwave for 2 minutes on High) and serve as a sauce with brochettes and rice.
About 30 minutes before meal is served, combine rice, salt and water in large saucepan. Bring to boil, and then simmer, covered for 15 minutes until water is absorbed. Turn heat off, stir in peas, cover for 5-10 minutes. To mold, press hot rice into round or oval container, invert on plate, and tap to loosen mold. Garnish plate with reserved pepper "confetti."