Heat a small saucepan over medium-high heat. Add the balsamic vinegar and maple syrup to hot pan, bringing to a boil. Continue cooking, stirring ever few minutes. Allow the mixture to cook until it has reduced to the consistency of a thing syrup. This should take about 5-7 minutes. Set the balsamic glaze aside to cool.
Add watermelon, avocado, onion, and mint to a large bowl. In a small bowl, whisk together olive oil, lime juice, and salt. Pour dressing over the watermelon mixture and toss to combine. Drizzle with balsamic glaze and serve immediately.
Recipe Notes
Balsamic glaze can easily be purchased at the grocery store if the homemade version is a step you’d like to skip.