In a large enameled cast-iron casserole or Dutch oven, cook the bacon strips over moderately low heat, stirring occasionally, until lightly browned, about 8 minutes. Add the onion and cook over moderate heat, stirring, until very lightly browned, about 5 minutes. Stir in the bell peppers and garlic and cook, stirring occasionally, until softened and lightly browned, about 5 minutes longer. Stir in the sausage slices, crushed red pepper and paprika and cook for 2 minutes. Add the tomatoes and cook until beginning to break down, about 5 minutes. Add the beer and bay leaf and bring to a boil. Cover partially and cook over low heat until the vegetables are very tender and the sauce is slightly reduced, about 15 minutes. Season the stew with salt and pepper and serve with grilled bread.