01 - Preheat grill to medium-high heat (about 400°F).
02 - Brush both sides of each watermelon wedge lightly with olive oil.
03 - Sprinkle watermelon evenly with sea salt and black pepper.
04 - Place watermelon wedges on grill and cook for 2-3 minutes per side until grill marks appear and fruit is slightly caramelized.
05 - Remove from grill and transfer to serving platter. Immediately drizzle with lime juice, then sprinkle with lime zest and chopped cilantro.
06 - Add chili flakes if desired. Serve immediately as a side or light appetizer.