Place chicken in a resealable plastic bag set in a shallow dish. For marinade, in a small bowl stir together juice concentrate, soy sauce, ginger, garlic salt, and cayenne pepper. Reserve 1/3 cup of the marinade for sauce. Pour the remaining marinade over chicken. Seal bag; turn to coat chicken. Marinate in the refrigerator for 4 to 24 hours, turning bag occasionally.
For sauce, in a small bowl stir together the reserved 1/3 cup marinade and brown sugar; cover and chill until needed.
Preheat oven to 375 degrees F. Drain chicken, discarding marinade. Arrange chicken in a shallow baking pan. Bake for 25 minutes. Brush both sides of chicken with some of the sauce. Bake for 15 to 20 minutes more or until chicken is done (at least 175 degrees F), brushing once or twice with the remaining sauce. If desired, sprinkle with green onions and sesame seeds.