Combine mayonnaise, dill, garlic powder, celery salt, pepper and Parmesan cheese in a small bowl. Arrange bread slices on baking sheet in a single layer. Broil 6 to 8 inches from heat for 30 to 45 seconds or until lightly toasted. Turn slices over; spread with mayonnaise mixture. Broil 1 minute or until lightly browned. Top each with tomato, green onion and olives. Serve immediately.