Bit late to this thread but thought I'd add my 2 cents if it can help anybody.
Singlemanforum.com has a lot of info for Vietnam, just requires some effort to look for it.
I don't have much experience in Hanoi specifically, but I did go to neko nuru and had a great time for relatively cheap. A rough rundown is you take a bath with the girl, then on to the table where a decent massage follows.
The girl then licks you all over, sucks you off for a bit then finishes with hand.