Cut the watermelon into bite-sized cubes, approximately 1-inch in size. Remove any seeds if necessary. Place the cubed watermelon in a large bowl.
Thinly slice the red onion. If you find red onion too pungent, you can soak the slices in cold water for 10 minutes to mellow the flavor. Drain well before adding to the salad.
In a small bowl, whisk together the olive oil, lime juice, salt, and black pepper. Pour the dressing over the cubed watermelon and gently toss to coat evenly.
On a large platter or individual plates, arrange the dressed watermelon cubes. Scatter the crumbled feta cheese and thinly sliced red onion over the watermelon.
Sprinkle the chopped fresh mint over the salad.
If desired, drizzle balsamic glaze over the salad for an added touch of sweetness and complexity.
Serve the salad immediately to enjoy the freshness of the ingredients.
Notes
This salad is best served immediately. Adjust the amount of balsamic glaze to your liking.