I got it at Num Pang. A Vietnamese sandwich shop in NYC. Really couldn't tell you exactly what was in the Cole slaw that made it so damn spicy. There must have been hot peppers sliced really thin (and unrecognizable). There wasn't any mayo but it was more vinegary without being traditionally vinergy like southern Cole slaw.
Apparently Num Pang is a Cambodian sandwich shop.
Cambodian Slaw (spicy) $3.25
Napa Cabbage, Red Cabbage, White Cabbage, Soy Sprouts, Bell Peppers, Fresh Herbs, House Dressing