Preheat oven to 450 degrees F.
In a heavy bottom 6-quart pan, heat olive oil until smoking. Add onion, shiitakes and chorizo and cook until onion is softened, about 8 minutes. Add Cinzano and bring to a boil. Add tomato sauce, wine and clams, cover and cook until clams are open, about 10 minutes.
Meanwhile, slice baguette as if to make a submarine sandwich. Brush bread with wine, then oil. Sprinkle with garlic and thyme and close. Place in oven unwrapped for 5 minutes. Remove and cut into 4-inch pieces. Uncover clams and serve immediately.