For Salsa: Bring large pot of water to boil. Add tomatoes and blanch 20 seconds. Transfer to bowl of cold water, using slotted spoon. Drain. Remove tomato skins using small sharp knife. Seed and chop tomatoes. Transfer to large saucepan. Mix in onion, bell pepper, vinegar, cilantro, bay leaves, jalapeño, salt and pepper. Simmer until thickened, stirring occasionally, about 1 hour. Remove bay leaves. (Can be prepared 1 day ahead; refrigerate. Bring to room temperature before continuing.) If using sausage, heat heavy large skillet over medium-high heat. Add sausage and cook until brown, crumbling with fork. Transfer to paper towel to drain, using slotted spoon.
For Pizza: Prepare barbecue (medium-high heat). Brush grill with olive oil. Place pizza crust on grill and cook until golden, about 3 minutes. Turn over. Sprinkle cornmeal on cooked side of crust. Spread 1 1/4 cups salsa over (reserve remainder for another use). Top with cheese, cilantro, jalapeño and sausage. Cover with grill lid or tent with foil and grill until crust is cooked on bottom and cheese melts, about 5 minutes. Serve pizza, passing guacamole and sour cream separately.