Tuscan Lasagna Spirals

1 teaspoon(s) salt

1 tablespoon(s) olive oil

1 (about 1 pound) jumbo onion , finely chopped

4 clove(s) garlic , crushed with garlic press

4 slice(s) (about 3 ounces) bacon , cut into 1/4-inch pieces

1 pound(s) white mushrooms , finely chopped

1 pound(s) portobello mushrooms , stems removed and caps finely chopped

1 package(s) (10 ounces) frozen chopped spinach , thawed and squeezed dry

1 cup(s) (4 ounces) shredded Fontina cheese

1/2 cup(s) grated Parmesan cheese

1/4 teaspoon(s) coarsely ground black pepper

1 can(s) (28 ounces ) whole tomatoes in puree

1 can(s) (14 1/2 to 16 ounces) whole tomatoes in puree