Cut the melon into wedges and separate the flesh from the shell. Remove the seeds using a small knife and cut the flesh into 3-4 cm (approximately 1 - 1 1/2 inches) cubes. Rinse the clover and the watercress and shake dry. Whisk together the lime juice, apple cider vinegar, mustard, both oil and 2 tablespoons of water. Season with salt and pepper.
Mix the melon, the herbs, the dressing and sesame seeds in a large bowl and season the salad.
To serve, transfer into in small bowls for a summer snack.