01 - Preheat grill to medium-high heat, approximately 400°F.
02 - Brush both sides of each watermelon wedge evenly with olive oil.
03 - Sprinkle watermelon wedges with sea salt and freshly ground black pepper.
04 - Place watermelon wedges on the grill and cook for 2 to 3 minutes per side, until grill marks develop and the surface is lightly caramelized.
05 - Transfer grilled watermelon to a serving platter. Immediately drizzle with fresh lime juice, then add lime zest and chopped cilantro on top.
06 - Sprinkle chili flakes over watermelon for a mild kick, if desired.
07 - Present immediately as a refreshing side or appetizer.