Melanie: I too love the old Janmae Guey on Stockton but I am sure that it is gone forever. So I have looked all around Chinatown for a good replacement and have not been able to find one I can really recommed. But to my surpise I was drive by 2300 block of Noriega a few week ago and saw a long line of Chinese waiting to get into a Chinese deli.
So I stopped and got in line. The duck was as good if not better in favor than Janmae Guey. The prices where a little higher than Chinatown, but well within line.
The have full menu with limited Wor Choy (family dinner menu)
Cheung Hing Restaurant
2339 Noriega Street
San Francisco, CA
Just down the street from Jumbo's (after a full meal I can still shop for more food).
Be sure to ask for a extra container of the duck sauce. After you finish all the meat you can use the extra sauce and bones to make a stock for won ton (if you save some skin and meat you can have Shredded Duck Yee Foo Won Ton Soup).