I found this restaurant by accident, and have been back there almost every week - it's in the middle of a little strip mall, you have to really look out for it.
A & J Restaurant
1269 E. Valley Boulevard
Alhambra, CA 91801
Chef Chang is a master at this cuisine. Every dish we have had there has been really flavorful and expertly prepared. Some favorites: bean curd/peanut small dish with special sauce, spicy beef tendon noodle soup (handmade noodles), fried pork chop on rice, cold spicy noodles, and amazing potstickers and scallion pancakes. Plenty of choices for vegetarians too.
The restaurant is small, clean, and the staff is great but not particularly conversant in English, so don't get frustrated if you call. Prices average $6, small plates $2-$3
I think they are open from 11am, and closed on Wednesdays. Not sure when they close every evening.