Cut the Chorizo in quarters lengthwise and then slice into 1/8" pieces. Chop the onion and mince the garlic. Use a large dutch oven. Get it hot and add about a tablespoon of olive oil to the pan with the Chroizo and onion and cook until the Chroizo starts to brown and the onion starts to get soft. About 10 minutes. Quarter the tomatoes and add them to the pot with the minced garlic. Stir briefly and let them cook until the tomatoes start to get soft, about 5 minutes. Add the seafood stock, saffron, crushed red pepper and let it simmer for a few minutes more to let the flavors come together. Add your seafood cover and steam until cooked through. This will take about 8 minutes.