In a bowl combine together baking soda, cornstarch, Chinese cooking wine, soy sauce and sesame oil, mix well.
Add the beef and using your hands mix it well to distribute the marinade evenly, set aside for 15 minutes.
Place wok in a stove top and place in really high heat, once it starts to smoke add oil and swirl it around to coat the surface.
Let it reach the oils smoking point then add the beef in single layer as possible, leave it there without mixing for 30 seconds to a minute until brown on one side. Turn to the other side and leave it again for another minute. Now start to stir fry, continue doing so for 2 minutes. Remove beef from the wok.
Soak rice noodles in boiling water in a big bowl for 3 minutes, drain then set aside.
Combine the soy sauce, dark soy sauce and brown sugar, set aside.
Using the same wok add 2 tbsp oil bring heat to high then sauté ginger and onions.
Add the choy sum and stir fry for 30 seconds.
Add the noodles and the soy sauce sugar mixture, stir fry continuously for 2 minutes until sauce is evenly distributed. Add small amounts of water if needed so it does not dry out.
Add the beef back together with the bean sprouts and chives, season with salt if needed then stir fry for 30 more seconds.
Remove from wok, serve while hot.