Bring a large pot of water to the boil. Add a tablespoon of salt. Cook the pasta until al dente. Drain.
Meanwhile, heat the oil in a large frying pan over medium heat. Add the garlic and onion and saute until softened. Add the tomatoes and cook for 2 minutes. Add the tuna and cook for a further 4-5 minutes, until heated through. Add rockets and toss to combine. Season with salt and pepper.
Add pasta to the prepared tuna mixture in the large pan. Mix well and toss to coat.
Serve warm. Share and enjoy!