Add the remaining 1 tablespoon of olive oil, the leeks and crushed red pepper to the skillet. Cook over low heat, stirring occasionally, until the leeks are softened, about 8 minutes. Stir in the flour and cook for 1 minute. Add the tomato and wine and bring to a simmer, stirring well to scrape up any browned bits on the bottom of the skillet. Return the squid and its juices to the skillet and simmer, stirring occasionally, until the stew has thickened and the squid is very tender, about 50 minutes. Season with salt and black pepper.