5 tablespoon olive oil
1 large fennel bulb, trimmed, cut into 1/4 inch pieces
1 red bell pepper, cut into 1/4 inch pieces
1 yellow bell pepper, cut into 1/4 inch pieces
1/2 red onion, cut into 1/4 inch pieces
4 garlic cloves, minced
1/2 cup orange juice
1/2 tablespoon grated orange peel
2 tablespoon drained capers
4 6-oz 3/4 inch thick tuna steaks
Heat 4 tablespoon oil in heavy large skillet over medium-high heat. Add fennel, bell peppers, onion and garlic and sauté until vegetables are tender, about 7 minutes. Add orange juice and orange peel and cook 1 minute. Mix in capers. Season to taste with salt and pepper.
Meanwhile, prepare barbecue (high heat) or preheat broiler. Brush tuna with remaining 1 tablespoon oil. Season with salt and pepper. Cook to desired doneness, 2 minutes per side for medium.
Cut tuna digonally into 1/2 inch thick slices. Fan onto plates. Spoon sauce over and serve immediately.