'Ranch 99' is very Chinese focused and has a good selection although it is a bit pricey. 'Pacific Super' is another good Chinese/Southeast Asia supermarket; The prices are really good and the food is clean and fresh although the store itself is not kept up as well as at Ranch 99. I would recommend both, although Pacific Super has more Southeast Asian goods.
Pacific Super: Daly City, San Francisco and Vallejo (and Hawaii).
Ranch 99: Milpitas, Daly City, El Cerrito (probably other locations as well)
If you're willing to come to Oakland there are many Chinese grocery stores in Chinatown. Several are off Broadway on 8th. Also the Farmer's Market next to Oakland's Chinatown off Broadway Friday mornings has a definite Chinese flavor--lots of Chinese produce and live birds and orchids.
There are tons of chinese grocery stores, it all depends on size, cleanliness, price and how far you want to drive.
The one closest to you would be in San Mateo, I belive. It's on Hillsdale X Norfolk. I can't remember the english name off the top of my head. It's decent sized, but I don't care for their prices or quality.
I am not sure what you are looking for, but sometimes items from Chinese groceries stores can be found in Indian groceries store. I know there's an Indian grocery store in redwood city.
The next closest one I can think of is in Mountain view, on Castro. Very small. I haven't really been inside it myself.
There's also a bunch of ranch 99's all over the place. In cupertino, daly city/pacifica, fremont, berkeley. These are my personal favorites. They are clean and they have a really high turn over rate, so most of the stuff is fresh. I think you can find them via the phone book.
Lastly of course, there's SF. There are so many!! Try china town, clement st and Irving st.
Best of luck...