Toss mozzarella balls with olive oil, chopped basil, salt, and pepper, then set aside to marinate.
Whisk together olive oil, balsamic vinegar, honey, Dijon, salt, and pepper, then pour into a small bowl.
Place the dressing bowl in the center of a round platter and ring it with mixed greens.
Tuck cucumber slices around the greens to build the wreath shape.
Scatter tomatoes, marinated mozzarella, olives, and pomegranate seeds over the greens, tucking in basil as you go.
Slice red bell pepper into strips and arrange as a bow at the base of the wreath.
Season lightly, drizzle with balsamic glaze if using, and serve with dressing spooned on individually.