Heat the oil in a wide heavy pot. Coarsely grind the leeks, celery, garlic, parsley, cilantro, and red bell pepper in a food processor. Add to the oil. Sauté the ground mixture until all liquids evaporate. Add the cheesecloth, canned tomatoes, potatoes, wine, cayenne, cloves, bay leaves, paprika, saffron, salt, and water. Bring to a boil again. Reduce the heat to medium and cook, covered for 45 minutes. Add the fish and pepper, and cook another few minutes, just until the fish is cooked through. Press on the cheesecloth to release as much liquid as you can before discarding. Adjust the texture and seasonings.