Rinse the fish fillets and drain well. Cut each into 3 or 4 lengthwise strips and place in a nonreactive bowl. Combine the salt, black pepper, and 2 tablespoons lime or lemon juice. Rub the fillet strips with the mixture and set aside to marinate, unrefrigerated, for 20 minutes. Coarsely chop the onion, bell pepper, cilantro, and tomato, and add these, along with the chile and the remaining tablespoon of lime or lemon juice, to a food processor or blender. Process for several seconds to make a coarse paste. Heat the oil in a large skillet and add half the paste mixture and all the fish strips. Cook uncovered over medium-high heat for 5 minutes, using a spatula to turn over each fish piece carefully, for minimal breakage. Top with remaining paste mixture and 1/2 cup coconut milk. Continue to cook uncovered for another 5 minutes. Serve over rice.