Cut watermelon into evenly sized cubes and chill beforehand to ensure the salad starts cold and refreshing.
Thinly slice cucumber and red onion, keeping the cuts delicate for balanced texture and flavor.
Combine watermelon, cucumber, onion, and mint in a wide bowl, tossing gently to avoid crushing.
Sprinkle crumbled feta evenly over the salad just before adding dressing to maintain texture.
Whisk olive oil, lime juice, honey, salt, and pepper until well combined and balanced.
Drizzle dressing over the salad, toss lightly, and serve immediately for best freshness.