Cut red onions in small squares, add limes, salt and let it sit for 15 minutes.after wash it off the strong juice. Add limes again and salt let it sit for 30 minutes. Add the tuna, tomatoes cut in small squares, cilantro chopped, salt and pepper. Final add the Tuna, mix it by trying to break the thick pieces. Refrigerate for an hour to two before serving.

You can serve it wit small tortillas or any favorite starch.