Combine tomatoes, sugar, and vinegar in a saucepan over medium heat; cook 3 minutes or until sugar dissolves. Stir in parsley and next 6 ingredients. Set aside.
Score fish skin diagonally two or three times (to prevent curling), and sprinkle with salt and pepper. Sear fillets, skin-side down, in 1 teaspoon oil in a cast iron skillet over medium-high heat about 2 minutes. Press fillets flat with a metal spatula to prevent curling. Transfer skillet to oven, and bake at 450° for 5 minutes or until fish flakes with a fork.
Serve fillets skin-side up. Spoon sauce over fillets.