01 - Preheat a grill or grill pan to medium-high heat.
02 - Brush both sides of the watermelon slabs lightly with olive oil.
03 - Grill the watermelon slabs for 2-3 minutes per side, until grill marks appear and the watermelon is slightly caramelized.
04 - Remove watermelon from the grill and let cool slightly. Cut into bite-size cubes.
05 - In a large bowl or serving platter, combine grilled watermelon cubes, cherry tomatoes, and red onion.
06 - Sprinkle crumbled feta evenly over the top, then add fresh basil leaves.
07 - Drizzle with olive oil, balsamic glaze, and lime juice.
08 - Season with sea salt and black pepper to taste. Toss gently and serve immediately.