Oh man, I don't remember the name. Go down Cua Dai beach all the way down to the beach and take a left. There'll be all of the expensive beach-side restaurants to your right, dozens of them, and past that there'll be a few local seafood joints on the left side of the street. The last one just before a Y-intersection sells oysters to bring home for 70,000 a kilo (about 6 oysters). Tell them a guy with a white helmet recommended them to you, maybe they'll throw me a few free oysters, lol. To eat at the restaurant however will cost more than 70,000, because of labor, and it can be a bitch to open oysters. I've cut myself plenty of times during my learning curve, and once really deep, and the bacteria got into the cut and 24 hours later it hit me and I'd never been so sick in my life. I couldn't hold anything down and spent the entire night tossing and writhing in agony and my legs ached so badly with pain - it was excruciating. EXTREMELY DANGEROUS. Use protection. Best advice I can give is this: If it's taking too much force, you're doing it wrong. That goes for mechanics and other things as well. That's when shit breaks and blood gushes. Watch YouTube videos, go slow, and they'll open like butter. The pros can shuck an oyster in three seconds flat. Really need the right equipment/knife as well. So damn dangerous, use gloves/towels/etc. as much as you can and just study and watch on YouTube how the pros do it.
There are two types of oysters I've seen here. The big kind and the small kind. Different flavors. I prefer the larger kind.
Now I heard that a few km further down the street, at the red light intersection of An Bang beach, there are a few ladies who sell seafood by the side of the road and come April, they might have oysters for 35,000 a kilo. I could be wrong. All I know is that they grow tonnes and tonnes of oysters in Da Nang, just sickening amounts, and there's no reason why oysters shouldn't be cheap. Either case, I don't know whether the restaurant or the road-side venders will sell to foreigners for that price, let us know your luck.
I asked around in Saigon during Tet, and they wanted 20,000 for a single oyster. Everything is more expensive during Tet though, and they do open the oysters and serve them for you. A few times I've had oysters here served to me it seemed wrong. Like part of the oyster was missing or something, they were just so small compared to when I open them at home, like a switch or scam or incompetence or something. And to add to that they don't preserve and serve the oyster liquor. If they do that to you, send it back and insist they preserve the liquor. I would personally ask to watch them open the oysters or have them open them table side, or ask them to reduce the price and I'll open them myself at the table. They scam and overcharge like crazy anyhow, today alone I heard prices from 130,000 a kilo to 200,000 a kilo. Tell them to go kick rocks.
As an aside, Phnom Penh is an oyster paradise, but most of the oysters there are a specific variety, a smaller creamy kind and they don't save the oyster liquor (natural salty water/juice). Buy 10, get 10 free. A few places I went to were 20 small creamy oysters for 14,000 Riels/ $3.50 USD/70,000 VND. Real soft, don't even need a knife, a spoon will take them clean off. I would scoop out three at a time, put some salt and lemon juice, and have at it. It makes me cry just thinking about it. But I love the oysters here as well, I can't say which I like better. Same same but different. Lol no, I don't know what that means or why people say that. Maybe that's what they said during apartheid and segregation. "Ehh, it's same same, but different." Separate yet equal, that's right! Lol, it's like calling pro-lifers anti-choicers. What a bunch of douchebags. Hey, there are douchebag pro-lifers and douche-bag pro-choicers. Everybody's has an equal opportunity to be a douchebag in my book.