"You hungry?" Lydia Lee asks me, beaming in her bright pink Hello Kitty apron. "You look skinny." She stands in front of a steaming vat of fish stock, ready to scoop me a fresh bowl of udon. It's not even 11 a.m., but I can't turn her down. At Yo Yo's, which offers one of the most affordable lunches in all of San Francisco's Financial District, an order of udon noodle soup is just $9, and a six-piece tray of sushi is just $3.25.
If you're looking for a very solid, under-$20 lunch in Downtown Brooklyn, stop by Xifu. They make Shaanxi dishes like flaky rougamo stuffed with chopped pork, turqouise-tinged dumplings, and a great spread of noodle dishes. They also serve something we've never seen before: a burrito, using a griddled flour tortilla, that's loaded with stir-fried pork and julienned cucumbers. It won't be going on our best burrito guide anytime soon, but it's a fun and fusiony thing that kind of works.