For dressing, in a small bowl stir together the orange peel, orange juice, vinegar, pectin, and sugar until smooth. Cover and chill at least 3 hours or up to 24 hours.
Cook macaroni according to package directions; drain. Rinse with cold water; drain again.
Meanwhile, thaw scallops, if frozen. Cut any large scallops in half. Bring water to boiling; add scallops. Return to boiling. Simmer, uncovered, for 1 to 3 minutes or until scallops are opaque. Drain. Rinse under cold running water.
For salad, in a large bowl toss together cooked macaroni, cooked scallops, spinach, peas, onion, celery, and sweet pepper. Stir dressing; pour over salad. Toss to coat. Makes five 2-cup servings.