Slice the mini watermelon in half, using a spoon to scrape all of the fruit from the center of the melon. Place in a large blender.
Add the lemon juice, strawberries, sugar, and ice to the blender. Blend until pureed.
Pour lemonade straight from your blender, or pour into a pitcher. For an extra fun way to serve this drink, pour it into the two empty halves of the watermelon, add a skewered strawberry and lemon for garnish, then slurp your lemonade from a straw!