Arrange the arugula on a platter. Scatter the fruit, mozzarella, and red onion over the arugula, then drizzle with the balsamic and oil.
Season generously with pepper and salt and toss; season with more oil, vinegar, salt, and pepper to taste.
1 hour | Serves 4
15 minutes | Serves 6
30 minutes | Serves 3 to 4