1 1/2 lb cleaned squid 2 tablespoons fresh lemon juice 1 tablespoon red-wine vinegar 1/3 cup extra-virgin olive oil 1 large garlic clove, minced 1/2 teaspoon salt 1/4 teaspoon black pepper 1 small red onion, halved lengthwise, then thinly sliced crosswise (1 cup) 1/3 cup pitted Kalamata olives, halved lengthwise 2 cups cherry or grape…