In a large pot with a lid, heat up the extra-virgin olive oil and add the red onion and chili pepper, and let cook together until soft. Add the totani, and let cook for about a minute on medium heat, stirring continuously to avoid sticking.
Squeeze the cherry tomatoes with your fingers to remove the seeds and add to the pot. (To avoid a mess of seeds and juices, squeeze the cherry tomatoes submerged in a bowl of water.) Season with salt. Lower the heat, cover the pot, and cook for 2 to 3 minutes.
Meanwhile, cook the tubetti pasta in boiling salted water until al dent, about 8 minutes. Drain the pasta, saving some of the pasta water. Add the pasta to the large pot along with a little pasta water, and cook for a few more seconds allowing all the flavors to come together.
Lastly, add the parsley and finely chopped garlic to maximize the intensity of the flavors. Stir well and serve immediately.