El Yucateca Chipotle hot sauce, Tabasco, or my current favorite, Huy Fong Sriracha sauce.
Available at most, if not all Asian food stores. Another great product is Sambal Oelek Chili Paste from the same brand, Huy Fong
http://www.amazon.com/Huy-Fong-Srira.../dp/B0002PSOJW