Slice bread into 24 (1/2-inch-thick) slices, discarding ends.
Whisk together olive oil and next 3 ingredients. Brush evenly on one cut side of each bread slice.
Grill bread slices over medium heat (300° to 350°) 2 to 3 minutes on each side.
Stir together olive tapenade and parsley; garnish, if desired. Place green onion slices in a small bowl. Serve tapenade and green onions with bread.
Note: For testing purposes only, we used Cantaré Olive Tapénade, which can be found in the deli section of large supermarkets.