Boil the eggs. Place them in cold water and boil over low heat to prevent cracking.
Once boiled and cooled, peel the eggs, cut them in half, and carefully remove the yolks, setting them aside.
Combine mayonnaise, ketchup, tuna, and the reserved egg yolks (leave two yolks for decoration). Mix well to taste.
Fill each egg half with the tuna mixture.
Crumble the two reserved yolks and sprinkle them over the filled eggs for decoration.
Refrigerate the eggs, as they are best served cold. They are even more flavorful the next day.