For the vinaigrette, mix vinegar and honey well. Season with salt and pepper. Fold in the oil.
Peel onions and cut them into fine strips. Clean, wash and shake dry the rocket. Wash cucumbers, peel if necessary and slice finely. Clean and wash radishes and also slice them finely. Remove the seeds from the melon, cut out or dice the flesh with a ball cutter.
Mix everything with the vinaigrette and let it steep for about 15 minutes.