Drain the oil from the tuna and mash with a fork in a bowl. Add the Olio Extra Vergine d’Oliva Toscano IGP, potatoes, eggs, breadcrumbs, capers, and salt to taste. Mix to obtain a homogeneous mixture.
Arrange the mixture on baking paper and give it the salami shape. Roll it on itself and close the baking paper in a sheet of aluminum foil.
Boil the water and cook the tuna salami for about 40 minutes. Drain and, once cooled, leave to harden in the fridge for an hour.
Cut into slices and serve.