In a small mixing bowl, whisk together the lime juice, honey, olive oil, sea salt, and black pepper until the dressing is fully emulsified.
In a large chilled mixing bowl, combine the sliced cucumber, melon cubes, and red onion.
Drizzle the prepared dressing over the produce and toss gently with tokens to coat evenly without bruising the melon.
Gently fold in the torn mint leaves and crumbled feta cheese just before serving to maintain texture.
Serve immediately or refrigerate for up to 30 minutes to allow flavors to meld.