01 - Preheat the grill to medium-high heat, approximately 400°F.
02 - Using a basting brush, lightly brush both sides of each watermelon wedge with olive oil.
03 - Sprinkle sea salt and freshly ground black pepper evenly over the watermelon wedges.
04 - Arrange the watermelon wedges on the grill. Grill for 2 to 3 minutes per side, until charred grill marks form and fruit is slightly caramelized.
05 - Transfer grilled watermelon to a serving platter. Drizzle immediately with freshly squeezed lime juice, then top with lime zest and chopped cilantro.
06 - For additional flavor, sprinkle with chili flakes if desired.
07 - Serve immediately as a vibrant side dish or light appetizer.