Cut the watermelon into big wedges, then cut the flesh away from the skin. Slice the flesh into bite sized pieces.
Cut the cucumber in half then half lengthways too. Use a potato peeler to slice ribbons off the cucumber.Arrange the lettuce leaves in a large bowl, top with the watermelon, cucumber, feta and mint.Finally place all the dressing ingredients together (juice of 1/2 lemon, olive oil, honey) in a small bowl and whisk together with a fork. Season to taste.