In 12-inch skillet, heat 1 tablespoon oil on medium until hot. Add onion and cook 6 to 8 minutes or until soft and golden, stirring occasionally. Stir in garlic; cook 1 minute. Add tomatoes with their juice, vinegar, and 1/8 teaspoon coarsely ground black pepper. Heat to boiling on medium-high. Cook 8 to 10 minutes or until thickened, stirring occasionally. Stir in olives and transfer tomato compote to bowl; cover to keep warm. Makes 2 cups.
Remove and discard tough crescent-shaped muscle from each scallop. Pat dry with paper towels. Evenly season scallops, on both sides, with 1/4 teaspoon salt and 1/8 teaspoon pepper.
In clean 12-inch skillet, heat remaining 1 tablespoon oil on medium-high until hot. Add scallops and cook 5 minutes or just until opaque throughout and lightly browned on both sides. Serve scallops with tomato compote.