1. To prepare orzo, cook pasta according to package directions, omitting salt and fat; drain. Place pasta in a bowl; stir in rind and next 4 ingredients (through 1/8 teaspoon black pepper). Toss to combine.
2. To prepare fish, combine fennel seeds, 1/4 teaspoon salt, and 1/8 teaspoon black pepper; stir well. Sprinkle both sides of the fish with fennel seed mixture. Heat 2 teaspoons oil in a large nonstick skillet over medium-high heat. Add fish to pan; sauté 5 minutes on each side or until fish flakes easily with a fork or until desired degree of doneness. Transfer to a plate, and keep warm.
3. Heat remaining 2 teaspoons oil over medium-high heat. Add onion and red pepper flakes to pan; sauté 1 minute. Add garlic; sauté 15 seconds. Stir in tomatoes and capers; cook 2 minutes. Remove from heat; stir in basil and remaining 1/4 teaspoon salt. Divide pasta evenly among each of 4 plates; top each with 1 fillet. Spoon 1/3 cup tomato mixture over each serving.