Onions peel and in each case in 6 columns cut. Wash and dry the corn on the cobs.
Heat the oil in a frying pan. First fry the corn on the cobs while turning. Season with salt and pepper, remove from the pan and let it cool down. Sauté the onions in the hot frying oil while turning, sprinkle with sugar, add vinegar and allow to caramelize briefly.
Remove from the pan and let it cool down.
Cut the ham slices in half lengthwise. Put 1 corn calf, 1 onion wedge and 1/2 slice of Parma ham on 1 skewer. Arrange skewers with some salsa sauce in small bowls.