01 - Heat your grill to medium-high temperature (approximately 400°F).
02 - Lightly brush both sides of each watermelon wedge with olive oil, then season evenly with sea salt and black pepper.
03 - Place seasoned watermelon wedges on the preheated grill. Cook for 2 to 3 minutes per side until distinct grill marks form and the edges begin to caramelize slightly.
04 - Transfer grilled watermelon to a serving platter. Drizzle with fresh lime juice, then sprinkle generously with lime zest and chopped cilantro. Add chili flakes if desired for additional heat. Serve immediately while still warm.