For the dressing mix the pumpkin seed oil, vinegar, salt, pepper and sugar together well. Dice the onion very small and mix with the dressing. Now fold in the lamb`s lettuce.
Cut the Parma ham thinly and the feta cheese into cubes. Remove the inside of the melon and cut fan-shaped pieces.
Arrange everything nicely on plates. Possibly pull a few threads from the pumpkin seed oil over the finished plate.