Best Asian/Chinese supermarket in Van??
I dunno about "best", but T&T is a bit of everything to everyone, and with all their locations in major town centres, they are convenient and accessible.
The best Asian/Chinese produce stand is the one closest to you that provides most of what you need on a daily basis, with value, quality and good service thrown in. And hopefully a Mom & Pop operation. Everyone has their own "favorite" best local green-grocer/deli (some may not be Asian/Chinese at all).
My own are: Sunshine Market (Oak/15th) and East West Market (Main/King Edward).