Heat the extra-virgin olive oil in a frying-pan and, when it is hot, add the diced pancetta. Let it brown over a low heat, stirring with a wooden spoon occasionally to prevent it from sticking. Meanwhile, cut the chili pepper in half on a cutting board. As soon as the bacon is browned, add the chili cut in two and the chopped tomatoes. If using whole peeled tomatoes, chop them before adding them. Add some salt if needed and continue cooking the sauce, stirring with a wooden spoon. Put a saucepan with plenty of water to boil, add salt and cook the bucatini al dente, then drain. Add the pasta into the frying pan with the sauce to finish cooking, tossing it for a couple of minutes. Turn the heat off, add the grated pecorino cheese, stirring well. Serve very hot.