Make a small incision in the skin of each tomato. Place them in boiling water and remove after 2 minutes. This will help you peel them easily.
Dice the peeled tomatoes. Fillet the anchovy.
Briefly fry the garlic and anchovy fillets in olive oil. Add the tomatoes, stir and cook over increased heat for 2 minutes. Season with salt lightly, add the rosemary, lower the heat and cook for about 15 minutes with a lid on, stirring occasionally. Once the tomato sauce is done, add the tuna, season with lemon pepper and additional salt if needed. Cook over low heat for another minute.
If the sauce is too thick for your taste, add a few drops of olive oil.
Cook the pasta according to the instructions on the packaging, in a large pot of salted boiling water. Top the drained pasta with the tuna sauce and serve warm.