I have had mixed success with sous vide Chinese dishes. I have had great success with char siu, Hoi Nam/Hainanese/white cut chicken -- dishes that I make almost exclusively sous vide now because of the superior results -- and various braised pork belly dishes.
I've had much less success with vegetable dishes, and have had some really inedible disasters -- I wasted some beautiful spring bamboo shoots a few weeks ago which would have been much better poached or steamed but wound up horribly bitter (maybe from cyanide which won't flash off or dilute like in a wok or boiling water). For beans and greens there is even less reason, as these things cook so quickly. For beans, I "break the rawness" by throwing them in boiling water for a minute or so -- in a restaurant they might do that in hot oil -- before stir frying them. Since you want your beans crisp, I don't see how sous vide could improve the texture of the final dish in any way. If the idea is to do the whole dish sous vide, with the spices and other ingredients in the bag, I don't think there is any way that could work for several reasons, including that the spices would behave in unpredictable ways that are not likely to be good, and also that you would wind up with a watery, unreduced, and unthickened sauce. I'm a big fan of sous vide, and use it also for western simple vegetables (i.e., carrots, potatoes (packed with butter at 90C is a sure winner)) but for Chinese vegetables nothing is easier or better than a wok.
