Asian grocery store is probably the best place for men to pick up a single Hmong gal in her 30s. Simply just go and ask if she knows where to find dried Chinese yams. Choose an item that will actually draw her to walk down the aisle with you. Then to find out if she's single, maybe ask her what she is shopping for. If she's married she'll tell you right away. "I'm making pho for my family. The kids really want to eat pho."
If she's single, her response is typically, "my mom asked me to come get these items..."
Anyways, single gals tend to be shopping for their maternal family because they're having a small gathering of sorts. Sometimes she's with an older woman, her mom, or other females around her age (sisters, aunts, etc.). But you can usually tell who is single and who is not.
Then just start a conversation.
The problem is that at this age, women don't want to play around. If you're really interested then show it. Let them know your intentions immediately. Women don't want to get into long-time-boyfriend/girlriend-who-knows-where-this-is-going-to-end-relationships. Is this going to be 10 years of dating before tying the knot? Ridiculous!
If the guy has to think too much about it and wait then it's a CANCEL.
If you're a grown man in your 30s+, then you should know by the third month if you're going to marry this woman after seeing her.