Heat olive oil in a large, heavy skillet over medium heat.
Add the diced pancetta and sauté until golden brown, about 8 minutes.
Add the chopped onion to the skillet and sauté until tender, around 5 minutes.
Stir occasionally to prevent sticking.
Pour in the white wine, and stir, scraping up brown bits from the bottom.
Allow it to reduce slightly for about 2 minutes.
Add the peeled tomatoes and red pepper flakes.
Break up the tomatoes with a spoon and simmer on low heat for 15 minutes.
Season with salt to taste, stirring occasionally to incorporate flavors.
Adjust the seasoning as needed.