In a small bowl, conbime the pineapple juice, soy sauce, horseradish, parsely, 3 teaspoons sesame oil, honey and pepper. Pour 2/3 marinade into a large resealable bag; add the salmon ad green onions. Seal bag and turn to coat; refrigerate for 1 to1 1/2 hours, turning occasionally. Add the remianing sesame to remaining marinade. Cover and refrigerate for basting.
Coat the grill rack with cooking spray before starting the grill. Drain and discard marinade. Grill salmon, covered, over medium heat or broil 4-6 inches from the heat for 8-12 minutets or untiil fish flakes easily with a fork, basting frequently with reserved marinade.