Roast duck is not clear, because it is not a specialty of Nanjing. The best salted duck is Han Fuxing, but you can't buy it packaged in the supermarket, but you must buy it on the spot in the store and it tastes authentic, otherwise it will go bad. A shop in Han Fuxing is on Hunan Road, near Zhongshan North Road. You can go and have a look.