For marinade, combine soy sauce, lemon juice, garlic, ginger, and mustard. Cut chicken into 1-inch pieces; place in plastic bag set into a shallow dish. Add marinade; seal bag. Turn chicken to coat well. Chill for 2 to 24 hours, turning chicken occasionally.

Remove chicken from bag, reserving marinade. Cut green and red peppers into 1-inch pieces. On six 12-inch metal skewers alternately thread chicken, pineapple, green pepper, and red pepper. Grill on uncovered grill directly over medium coals for 5 minutes. Brush with marinade; turn skewers and grill for 7 to 9 minutes more or until chicken is tender and no longer pink. Serve over hot cooked rice and garnish with green onion brushes, if desired. Makes 6 servings.

Arrange preheated coals around a drip pan in a covered grill. Test for medium heat above pan. Place skewers on grill over drip pan. Cover and grill for 16 to 18 minutes or until chicken is tender and no longer pink, brushing occasionally with marinade up to the last 5 minutes of grilling.