These lettuce cups are filled with surprising and boldly flavored ingredients—crisped balls of sushi rice wrapped in paper-thin sheets of lardo (pork fat) and topped with fresh uni (sea urchin). Slideshow: Fast Hors d'Oeuvres
Tobanjan (spicy, fermented broad-bean paste, also sold as doubanjiang) and Chinese black vinegar are available at Asian food stores. Look for uni (sea urchin) at Japanese markets. Lardo is available at specialty and Italian food stores.