Place mixed greens on a large serving platter. Arrange tomato slices in center of platter over greens. Arrange Grilled Balsamic Vegetables and black olives around edge of platter over greens.
Whisk together olive oil and vinegar; drizzle over tomatoes and grilled vegetables. Sprinkle tomatoes evenly with basil, chives, and, if desired, marjoram. Top evenly with cheeses.