Pour 8 1/3 cups (2 liters) of water in a large pot. Add salt and oil. When the water comes to a boil, add the spaghetti. Boil them for as long as is written on their packaging. Once the noodles are ready, drain them.
In 4/5 cup (200 ml) water, put the tomato paste and chopped tomatoes, mix them well and add the mixture to the sauteed vegetables. Allow the sauce to simmer on low heat about 20 minutes, until thickened.
Add the salt, black pepper and a little sugar to taste. Serve the spaghetti with the sauce.