If a nuclear bomb were to detonate over the Bay Area, vaporizing thousands if not millions of innocents in a hot, bright flash, we have a feeling that, when the radiation began to clear, there would still be a line to get into Betelnut. Open since 1995, the place has already become a San Francisco institution, a result of the consistently excellent selection of small plates drawn from across East Asia. Every meal should begin with salt-and-pepper prawns and Celia's minced chicken in lettuce cups. From there, proceed to the wok-charred squid salad with Thai basil and lime, the Szechuan green beans, the little dragon dumplings, or maybe the meltingly tender braised short ribs in adobo sauce. Also, don't forget to order a Scorpion Bowl, which serves four people quite adequately, but really has an impact when shared between two.