In a large bowl, add the diced watermelon cubes (instructions for dicing the watermelon can be found above).
Wash the english cucumber and peel with a vegetable peeler. Cut the cucumber in half and then into quarters. Slice these quarters thin into small triangles of crisp cucumber and add the cucumber to the watermelon mixture.
Slice the green onions and seed the jalapeno, mince the jalapeno fine, and add to the bowl.
Chop up the fresh mint finely, and add to the bowl.
Crumble the feta cheese and add to the bowl.
In a small bowl or mason jar, add the minced or crushed garlic, balsamic vinegar, and olive oil. Season with salt and pepper, shake well.
Pour the dressing all over the juicy watermelon and toss well. Serve this refreshing salad immediately or chill for 1 hour.