01 - Preheat your grill to medium-high heat. Lightly oil the grates to prevent sticking.
02 - Cut the watermelon into rounds or wedges approximately 1-inch thick. Pat slices dry with paper towels to remove excess moisture.
03 - Place watermelon slices on the preheated grill. Cook for 2-3 minutes per side until distinct grill marks appear and fruit is lightly charred but still firm. Remove and set aside to cool slightly, then cut into cubes or triangles.
04 - In a small bowl, whisk together olive oil, balsamic glaze, Dijon mustard, honey (if using), salt, and pepper until fully emulsified.
05 - In a large salad bowl, combine arugula or baby greens, grilled watermelon cubes, cherry tomatoes, and red onion slices.
06 - Drizzle the balsamic dressing evenly over the salad. Using salad tongs, gently toss all components to coat thoroughly without damaging the ingredients.
07 - Top with crumbled feta cheese, fresh mint leaves, and toasted seeds or nuts if desired. Serve immediately while watermelon is still slightly warm.