01 - Preheat grill to medium-high heat. Lightly oil the grates to prevent sticking.
02 - Cut watermelon into rounds or wedges about 1-inch thick. Pat slices dry with paper towels to remove excess moisture.
03 - Place watermelon slices on the grill. Cook for 2-3 minutes per side until distinct grill marks appear while the fruit remains firm. Remove and let 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 well combined and emulsified.
05 - In a large salad bowl, combine arugula or baby greens, grilled watermelon pieces, cherry tomatoes, and red onion slices.
06 - Drizzle the balsamic dressing evenly over the salad. Using salad tongs, gently toss to coat all ingredients without damaging the watermelon.
07 - Top with crumbled feta cheese, fresh mint leaves, and toasted pumpkin seeds or pine nuts if desired. Serve immediately while watermelon is still slightly warm.