Incise the skin of the breast diamonds-shape. Rub with salt and pepper. Fry skin side down over medium heat for 15 minutes, turn and cook another 5 minutes. Mix the vinegar, oil, and 1 tablespoon of heated meat juice, salt, pepper and season with sugar. Cut the cherry tomatoes in half. Grate the Parmesan. Cut duck breast into slices. Put arugula and cherry tomatoes on a plate, place the breast on top, sprinkle with Parmesan and drizzle with marinade.