Brush fish evenly with 1 teaspoon oil; sprinkle evenly with 1/4 teaspoon salt and 1/8 teaspoon pepper. Combine remaining 1/2 teaspoon oil and 2 tablespoons juice. Set aside.
Combine 1/8 teaspoon pepper, prosciutto, fennel fronds, fennel seeds, and garlic, stirring well. Heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Sauté prosciutto mixture for 3 minutes or until prosciutto is crisp.
Cut fennel bulbs vertically in half. Grill 2 minutes on each side or until golden. Cut into 1/4-inch-thick slices. Keep warm.
Place fish on grill rack coated with cooking spray. Grill 5 minutes on each side or until fish flakes easily when tested with a fork or until desired degree of doneness, basting occasionally with juice mixture. Transfer fish to a serving platter; sprinkle fish evenly with remaining 1/4 teaspoon salt and remaining 1/4 teaspoon pepper. Top with prosciutto mixture, and drizzle with remaining 2 tablespoons juice. Serve immediately with grilled fennel and lemon wedges.