Thaw fish, if frozen. For beans, in a medium skillet cook the garlic in 1 tablespoon hot oil for 15 seconds. Stir in the undrained tomatoes and the sage. Bring to boiling; reduce heat. Simmer, uncovered, for 5 minutes. Stir in beans; heat through.
Meanwhile, rinse fish; pat dry with paper towels. Measure thickness of fish. Cut fish into 4 serving-size portions. Brush both sides of fish with the 2 teaspoons oil and the lemon juice; sprinkle with pepper.
Spray an unheated grill rack or grill basket with nonstick coating. Place fish on prepared rack or in prepared grill basket. Grill on an uncovered grill directly over medium-hot coals until fish flakes easily when tested with a fork (allow 4 to 6 minutes per 1/2-inch thickness of fish). If the fish is more than 1 inch thick, gently turn it halfway through grilling. (Or, place fish on the greased unheated rack of a broiler pan. Broil 4 inches from the heat for 4 to 6 minutes per 1/2-inch thickness. If the fish is more than 1 inch thick, gently turn it halfway through broiling.)
To serve, remove the skin from fish. Spoon beans on each serving plate and top with fish. If desired, garnish with additional fresh sage. Makes 4 servings.