Brush both sides of the watermelon slice with 1 tablespoon olive oil. Season with salt and pepper.
Grill the watermelon slice, cut side down on the grill grates and cook for 2 to 3 minutes. Flip the watermelon over and grill for an additional 2 minutes.
Transfer the watermelon to a platter and cut into 6 wedges.
Top with the arugula, blueberries, tomatoes and parmesan.
Drizzle with the remaining olive oil. Serve immediately.
Notes
Watermelon Pizza is best served soon after grilling.