I'm sure there are cultural differences between NYC and where I live, but I've found that any attempts at yelling "
Don't go the wrong way!", "
You're gonna kill yourself! Ride with traffic!" or something like that at a passing cyclist get no acknowledgment, get dismissed ("yeah, yeah, whatever"), or hostility. There's very few wrong-way cyclists that seem open to being educated.
I'm really hoping somebody can share some techniques that have seemed to reach the salmon.
I think the one thing I know of working is police ticketing them, especially since here one of their options for dealing with the ticket is taking a bicycle safety class from a LAB certified instructor via the local cycling advocacy group. In the US there's been federal grant money for "bicycle safety" that police departments can apply for to pay for overtime for police officers to concentrate on ticketing cyclists for dangerous illegal behaviors. It might be possible to convince your local police department to apply for some of that funding.
As far as how to keep yourself safe, hugging the curb and slowing down works great. Since they can see the oncoming traffic they're better situated for a dodge out of the bike lane. Slowing down so that you can stop quickly is helpful, too. If there's cars next to you, this doesn't work as well, since wrong-way cyclists are generally willing to ride in the door zone without thinking twice about it.