Prepare the pasta in boiling salted water according to the instructions on the packet. In the meantime, wash the lemon hot, grate dry and finely grate the peel. Clean the chilli, cut lengthwise, wash and remove the seeds. Chop the pod finely. Wash the parsley, shake dry, pluck leaves from the stalks and chop except for a few leaves for garnishing. Slice cheese. Drain capers and tuna.
Mix tuna with capers, lemon peel, chilli and chopped parsley. Drain the pasta, collecting the cooking water. Measure 100 ml and add to the pasta with oil and tuna mixture. Mix, heat again briefly and season with salt and pepper. Arrange on plates and garnish with parsley.