The radical concept behind Atoboy is to offer its customers the opportunity to build a three-course meal around the typically free Korean side dishes called banchan, but — and here’s the radical part — they charge you $42 for the privilege. To be fair, these aren’t the plates of pickled vegetables and tiny fermented fish you get on 32nd Street or in Flushing. Rather, they’re little marvels of perfection, like corn leavened with Taleggio, bacon, and soybean paste; octopus cut into precise nuggets, dusted in cornstarch, fried, and plated like a wagon circle around a chorizo-and-kimchee centerpiece; and fat fingers of fried chicken encased in crisp tempura shells on a slick of peanut-y sauce. Chef-partner Junghyun Park worked at the fine-dining Korean restaurant Jungsik, and his approach combines Western ingredients and techniques with the flavors he grew up eating. The concrete-clad room is spare with neat rows of tables set with copper buckets for storing napkins and chopsticks. And the service, led by the chef’s wife and partner, Ellia Park, is polished and smart.