Rinse the fish fillets and drain well. Cut each into 3 or 4 lengthwise strips and place in a 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, un-refrigerated, for 20 minutes.
In a food processor or blender, combine tomato, onion, bell pepper, cilantro, and chile pepper. Process for several seconds to make a coarse paste.
In a large skillet, heat the oil over medium-high heat. Add half the paste mixture and all the fish strips and cook for 5 minutes, using a spatula to turn over each fish piece carefully, for minimal breakage. Top with remaining paste mixture and the coconut milk. Continue to cook for 5 minutes.
Serve over rice.