Cook the thinly-sliced onion in a little Sottolestelle extra-virgin olive oil and water in a saucepan until transparent. Peel the tomatoes, remove the seeds, chop into cubes, and add to the onion. Add salt and cook for approximately 30 minutes. Cook the Sottolestelle Traditional Orecchiette in boiling salted water, drain. Serve with the tomato sauce and sprinkle with grated cacioricotta.