I scoured the giant Chinese market for a can of fried dace with black bean, and came up empty. Haven’t had time for a shopping trip since then. So I was on this dish but quick.
The A Lee 88 menu does specify “bok choy” but it is sliced thinly across a diagonal so it’s a bit hard to tell visually. Based on the taste, I could see it being celtuce - or what my spouse’s family calls A-tsai - but in my experience that has always been a giant stalk that gets peeled & cut up like a kohlrabi into batons, not a smaller stalk with leaves attached, as this dish was. Could just be a baby version, of course, or maybe just something else entirely, as my experience is not exhaustive in this arena.