For the bean salad, wash the pointed peppers, remove the seeds, quarter and cut into strips. Slice the onion and olives, drain and rinse the beans.
Mix the previous ingredients in a bowl. Crumble the feta cheese over it, add the tuna along with the oil to the bowl. Drizzle with a little olive oil and gradually add the lemon juice until the desired acidity is reached.
Season with salt and pepper and serve with white bread, baguette or ciabatta.