Cube the watermelon into 1-inch pieces and transfer to a large mixing bowl. Dice the cucumber into comparable-sized chunks and combine with the watermelon. Slice the red onion into thin slivers and add to the bowl. Roughly chop the mint and basil, then set them aside separately—you'll add them later to preserve their freshness.

Place the honey, freshly squeezed lime juice, olive oil, and salt in a jar with a secure lid. Close tightly and shake energetically for 10 to 15 seconds until the honey fully dissolves and the dressing becomes slightly emulsified. The vigorous shaking prevents the honey from settling at the bottom.

Break the feta into bite-sized crumbles directly over the bowl containing the watermelon mixture. Drizzle the prepared dressing from the jar over everything and sprinkle with black pepper. Toss gently using a light hand to coat all ingredients evenly while keeping the watermelon cubes intact and avoiding excessive mixing of the feta.

Scatter the reserved chopped mint and basil over the dressed salad and toss once more gently to distribute the herbs evenly. Serve right away while the watermelon remains cold and the herbs are at peak freshness.