I;'ve been searching all over LA for the authentic New York recipe, a la Ollies. Only a few Chinese places make it, and all those I've found make a thin, mediocre prioduct. The First Szechuan Wok in Westwood used to have a New York Chef who make a pretty good version, but it went sharply downhill about 2 or 3 years ago.
The real NY version should have a thick peanut/sesame sauce, not a thin coating. And faking it by using sesame oil on the noodles is a no no.
Among the failed versions is Uncle Chen on Ventura, and Hunan Cafe on Sunset.
The dish is often called Ma Jaan Leun Mein (Cold Noodles Sesame Sauce) and sometimes Dan Dan Mein (though there are often completely different dishes that go by that name including some served warm).