If nice fresh roma tomatoes are not available, substitute two 28-ounce cans whole peeled roma tomatoes, drained and chopped (should be about 3 cups). Reduce the salt to 1/4 teaspoon.
To peel and seed tomatoes: Cut a shallow X on the base of each tomato. Using a slotted spoon, dip tomatoes into boiling water for 15 seconds, then transfer to cold water. When cooled slightly, use a paring knife to gently pull off the skin. To remove the seeds, cut the tomato in half and scoop or squeeze out the seeds.