Finding the secret ingredients for fried green beans

Fried green beans was one of our favourite side dishes in Beijing. It is a staple in Chinese homestyle cooking but, done well, it’s delicious. There were a few ingredients I needed to go looking for in order to try out this recipe back here in Ireland.
Sichuan peppers were easy – Shan had brought a supply with her when she visited us at Christmas. The distinctive numbing sensation on the tongue and lips is not easily mistaken for anything else.
This is what they look like:

The dry leafy vegetable that she didn’t think I could find in Ireland was trickier to identify So I asked Shan to text me the pin yin and Chinese Characters for the vegetable in question. It’s called “mei gan cai” or 梅干菜. I took myself off with that information to the Asia Market in Drury St. Dublin. which is a great source of all manner of spices and sauces as well as offering great value in fresh fruit, vegetables, meat and fish.
Through a process of elimination using photos exchanged via iMessage,we identified this as the correct product:

I’m still not sure what this is so any suggestions would be welcome. Could it be a type of dried mustard leaf?