Combine the ingredients (starting with just 2 tablespoons of lime juice) in a saucepan and bring the mixture to a simmer over medium heat. Cook for approximately 10 minutes, enough to slightly thicken the sauce. The vegetables should soften a little yet still stay crisp-tender. Taste and add the additional lime juice if desired. Refrigerate the sauce for at least 1 hour to allow the flavor to develop. Serve the sauce chilled. It keeps, refrigerated, for several days.

* Variations: For a green sauce, substitute an equal amount of pureed fresh or canned tomatillos for the canned crushed tomatoes and reduce the amount of lime juice to 1/2 to 1 tablespoon.