We found a wonderful, tiny restaurant very near the Great Wall at Mutianyu called Xiaolumian. http://www.xiaolumian.com/. It's rustic. But it's a very clean place. Very hard to find, too.
As the name suggests, it is located in a small road. Very small road. Xiao=small, Lu=road, Mian=noodle. Thank God for a kind and resilient taxi driver who keeps using his handphone to ask for directions from the restaurant.
We finally reached the place and was delighted with the smiling waitress who is a local living in Mutianyu. And... speaks english!
The dumplings are tasty. The noodles fresh and, mixed with the sauce, is wonderful. I also enjoyed the freshly cut vegetables they prepared for us.
What a unique, traditional chinese meal. Kudos to my hubby who found it when he researched the internet.