Method:
In a bowl, mix all the above ingredients. Make a paste but do not mash it completely - you want some chunks of the tuna to be visible.
Cut the buns into two and pan toast them until crispy on the outside (or throw them in the air fryer for about three minutes).
Arrange the lettuce on one half of the bun.
Add a tablespoon of the tuna mixture and add another layer of lettuce, then add an extra tablespoon of the tuna mixture.
Cover with the other half of the bun, and repeat the process with the rest of the buns. Enjoy!