Cut watermelon into 1-inch cubes.
Cut feta cheese into ½-inch cubes.
Wash and dry mint leaves completely.
Thread one watermelon cube onto skewer.
Add one mint leaf (fold if needed).
Add one feta cube.
Add another mint leaf.
Finish with another watermelon cube on top.
Repeat for all 12 skewers.
Arrange on serving platter.
If using drizzle, mix balsamic glaze and olive oil. Drizzle lightly over skewers.
Sprinkle with black pepper and sea salt flakes if desired.
Garnish with extra mint leaves.
Serve immediately or refrigerate up to 2 hours.