Grilled Tuna with Olive Relish

Name: Grilled Tuna with Olive Relish
Ingredients: Olive Relish; ½ cup finely chopped fresh parsley; ⅓ cup chopped pitted imported black olives, such as Kalamata; ¼ cup finely chopped celery; 1 small clove garlic, minced; ½ teaspoon dried oregano; 1 tablespoon lemon juice; 1 teaspoon extra-virgin olive oil; ⅛ teaspoon salt; Freshly ground pepper, to taste; 1 3/4 pounds tuna steak, trimmed and cut into 6 portions; 1 tablespoon extra-virgin olive oil; 1/4 teaspoon salt; 1/8 teaspoon freshly ground pepper; Lemon wedges, for garnish