For the tuna spaghetti, bring a pot of salted water to a boil and cook the spaghetti al dente for about 9 minutes.
In the meantime, heat a pan with olive oil and sauté the finely chopped onion, garlic and chili. Add the chopped zucchini and tuna.
Then add the halved cocktail tomatoes and sauté for a few minutes. Toss the al dente cooked spaghetti with the tuna-vegetable oil, dress and serve with Parmesan cheese taken care of.