Cut fish steak into 6 serving pieces.
Place in ungreased square baking dish, 8x8x2 inches.
Mix 1/4 cup lemon juice, 2 tablespoons oil, the garlic, chili powder, cloves and 1 teaspoon salt; pour over fish.
Cover and refrigerate at least 2 hours.
Cut cucumber lengthwise into fourths; remove seeds.
Cut each fourth lengthwise into thin slices.
Remove fish from marinade; reserve marinade.
Place fish on rack in broiler pan.
Set oven control to broil.
Broil fish with tops 2 to 3 inches from heat until light brown, about 5 minutes.
Turn carefully; brush with marinade.
Broil until fish flakes easily with fork, 5 to 8 minutes longer.
Heat 1 tablespoon oil in 10-inch skillet over medium heat until hot.
Add cucumber.
Cook and stir just until cucumber is crisp-tender, about 2 minutes.
Toss with 1 tablespoon lemon juice, 1/8 teaspoon salt and the fennel seed.
Serve cucumber with fish.