PREP: 20 minutes CHILL: 2 to 24 hours MAKES 4 sandwiches 1 cup chopped yellow summer squash and/or zucchini 3⁄4 cup chopped broccoli 2⁄3 cup seeded and chopped roma tomatoes (2 medium) 8 pitted kalamata or ripe olives, chopped 2 tablespoons snipped fresh Italian...
