Cut the watermelon by trimming the ends, slicing around the equator, and cutting into quarters or eighths. Remove the rind, making sure to get rid of the white pith.
In a small bowl, whisk together the white balsamic vinegar, minced garlic, brown sugar, olive oil, sea salt, and black pepper until well combined.
In a large serving bowl, combine the watermelon, cucumber, red onion, crumbled feta, mint, and basil. Drizzle the dressing over the salad and gently toss to combine.
Sprinkle with additional feta, mint, basil, and a pinch of sea salt if desired.