Rub the inside of both halves of the bread with the garlic to flavor it. Using a pastry brush, thoroughly imbibe the inside of the bread with the olive oil. Sprinkle lightly with vinegar, salt and pepper.
Mix together all of the other ingredients: lettuce, tomatoes, eggs, tuna, anchovies, cucumbers, bell pepper, red onion, basil and olives. Place the mixture inside the bread and replace the top on the bread. Wrap in plastic wrap and refrigerate for 1 hour before slicing and serving. You might like to place a weight on top of the sandwich while it is "marinating" to help solidify the ingredients.
You could also add chopped radishes and artichoke hearts, which I'm sure some people consider essential ingredients to this tuna fish sandwich recipe. But most importantly, you should add what pleases you.