01 - Preheat grill to medium-high heat. Lightly oil the grates to prevent sticking.
02 - Cut watermelon into rounds or wedges approximately 1-inch thick. Pat dry thoroughly with paper towels to remove excess moisture.
03 - Place watermelon slices on preheated grill. Cook for 2-3 minutes per side until distinct grill marks appear while maintaining firm texture. Remove and set aside to cool slightly.
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, cooled grilled watermelon cut into cubes or triangles, cherry tomatoes, and red onion slices.
06 - Drizzle balsamic dressing evenly over salad mixture. Gently toss using salad tongs to coat all ingredients without damaging the watermelon.
07 - Top salad with crumbled feta cheese, fresh mint leaves, and toasted pumpkin seeds or pine nuts if desired. Serve immediately while watermelon retains slight warmth.