Preheat oven to 350°F.
1. In a small bowl, combine sour cream, mayonnaise, onions, lemon juice, lemon zest, onion powder, 1⁄2 tsp dill, salt-free seasoning, and salt. Mix well. Set aside.
2. Spray a baking dish with nonstick cooking spray. Place the halibut fillets in the dish.
3. Spoon sour cream mixture over fillets. Bake uncovered for 30 to 35 minutes or until fish flakes easily with a fork.
4. Top fillets with remaining 1⁄2 tsp dill and pepper. Serve with hot rice and lemon wedges on the side.
Makes 4 servings.