Prepare the ingredients as instructed above.
In a bowl, combine the drained tuna, mayonnaise, Dijon mustard, chopped olives, chopped parsley, salt, and black pepper. Mix well.
Optional, toast the rolls.
Layer the roll with lettuce, tomato, onion, tuna salad, and olives. Place the other half of the roll on top. Cut in half.
Serve the bocadillo de atún with chips, pickle, and pink lemonade.