Start by cutting the rind away from your watermelon, then slice the fruit into bite-sized one-inch chunks. Place the cubes in a colander so any extra juice can drain away. This keeps your salad from getting watery once you add the dressing.
In a small bowl, whisk together the olive oil, fresh lime juice, salt, and black pepper. Keep whisking until everything looks well combined and slightly emulsified. This simple dressing is what ties the sweet melon and salty cheese together.
Transfer your drained watermelon chunks into a large salad bowl. Pour the dressing over the top along with the chopped fresh mint. Gently toss everything together so the watermelon gets evenly coated without turning mushy.
Sprinkle the crumbled feta cheese over the dressed watermelon and mint. Stir very gently so the cheese distributes throughout without breaking apart the watermelon cubes. Go slow here you want distinct chunks of feta, not a mushy mix.
This salad tastes best when served immediately after tossing. The longer it sits, the more the watermelon releases its juices, which can water down the flavors. Serve it right away for the freshest, most vibrant taste.