If using live snails, steam them over boiling water for 1 hour, or until they leave their shells.
In a 10 to 12 inch sauté pan, heat the olive oil over medium heat until smoking. Add the onions and garlic and cook until softened and lightly browned, 8 to 10 minutes. Add the thyme, snails, wine, tomato sauce and olives and bring to a boil. Lower the heat and simmer for 30 minutes. Season with salt and pepper and transfer to a storage container and rest overnight in the refrigerator
The following day, bring 6 quarts of water to a boil and 2 tablespoons salt.
Meanwhile, in a 10 – 12 inch sauté pan, heat the already made snail ragu, set over medium low heat until just a boil and remove from the heat. Drop the spaghetti into the boiling water and cook until 1 minute less than the time listed on the package instructions.
Remove the pasta and drain well. Then toss into pan with snails and place pan over medium heat and toss until well coated, about 30 seconds.
Pour into a large heated bowl, drizzle with remaining olive oil and serve immediately. Sprinkle each portion with toasted breadcrumbs.
*Make dried crumbs by drying fresh, not stale, bread in an oven at very low temperature and then making crumbs of it in a food processor. Grind slices or chunks of bread to the desired size in the processor.