Arrange tomatoes and cheese in an alternating line, or make towers with a slice of each.
Fresh basil – either keep the leaves whole or julienne them, then arrange over the tomatoes and cheese.
Pesto – dot it here and there on the tomatoes and cheese.
Sprinkle the diced onion over the caprese.
Drizzle with oil and vinegar.
Sprinkle with oregano, salt, and pepper.
Serve immediately with bread.