If using wild-caught snails, starve them for a few days in a clean container so they purge their gut, then wash them thoroughly. With store-bought, pre-cleaned snails, skip this step.
Cook the snails with the bay leaf, the half onion and a few peppercorns: start them in cold water so they come out of their shells more easily, skim off the foam, and add salt only once it reaches a boil.
Meanwhile, in a pan, fry the tomato sauce, the chorizo slices and the diced ham in olive oil. You can also add a hot pepper to taste.
When the snails are cooked, add them to the tomato mixture and let them simmer together for a few minutes.