Onigilly, a food truck serving onigiri, the handheld Japanese seaweed-wrapped rice snack, is in downtown SF midday every weekday. With high hopes I tried it; I was disappointed.
At 11:45 they had already sold out of one of the four daily flavors. I tried marinated eggplant and miso (cooked, flaked) tuna. Each filling sits on a triangle of gummy brown rice, wrapped in a sheet of nori seaweed. The miso tuna had no miso taste, and both onigiri were undersalted. Because both fillings were moist, the seaweed got soggy quickly.
Onigiri in Japan are a ubiquitous delight. Every corner store (7-11, AM/PM, etc.) has a case of them, and they're cleverly wrapped so the nori does not touch the rice until you unwrap it and start eating, thus staying crisp. The fillings are entirely inside perfectly cooked white rice -- the moist filling never touches the seaweed, and white rice lets the fillings stand out much better than Onigilly's brown rice. Because onigiri are mostly starch, the filling tends to be very salty (and sometimes also very sweet), like salty roe, or sweet-soy shredded kelp (kombu tsukudani), or other intense fillings.
Onigilly does not do onigiri justice.
San Francisco, San Francisco, CA