Thaw fish, if frozen. Rinse fish; pat dry with paper towels. Cut fish into six serving-size pieces, if necessary. Measure thickness of fish. In a shallow dish combine flour, 1/4 teaspoon of the salt, and the black pepper. Coat fish on both sides with flour mixture.
In a 12-inch skillet cook fish in 1 tablespoon of the oil until golden, adding additional oil to skillet during cooking, if necessary. Allow 5 to 6 minutes per 1/2-inch thickness). Transfer to a serving platter; cover and keep warm.
Meanwhile, for sauce, in a medium saucepan cook onion and garlic in remaining 1 tablespoon oil until onion is tender. Stir in tomatoes, olives, lime juice, capers, the remaining 1/4 teaspoon salt, and the chile peppers. Bring to boiling; reduce heat. Simmer, uncovered, about 5 minutes or until desired consistency. Stir in oregano. Season to taste with salt and pepper.
To serve, spoon sauce over fish. Serve with hot cooked rice.