Thaw fish if frozen. Preheat broiler. Rinse fish; pat dry with paper towels. Set aside.
Place cauliflower and/or broccoli in a large microwave-safe bowl; add 2 tablespoons water. Cover with vented plastic wrap. Microcook on 100% power (high) for 2 minutes; drain.
In a small bowl combine paprika, chili powder, garlic powder, salt, cumin, and black pepper. Transfer half (about 1-1/2 tablespoons) of the spice mixture to a large piece of waxed paper. Gently roll fish fillets in spice mixture to coat. Toss drained vegetables with remaining spice mixture in a large bowl.
Coat the bottom of a 15x10x1-inch baking pan with nonstick cooking spray. Place fish fillets on one side of the pan and vegetables on other side of the pan. Turn under any thin portions of fish to make uniform thickness. Coat tops of fish with nonstick cooking spray.
Broil fish and vegetables 4 inches from the heat for 8 to 12 minutes or until fish flakes easily when tested with a fork and vegetables are crisp-tender, carefully turning fish and stirring vegetables once halfway through broiling.