In a bowl, combine the cabbage, radish, carrots, scallions, and cilantro. Whisk together the ingredients for the sauce and pour over the vegetable mixture. Allow to sit while making the noodles.
Bring a pot of water to a boil, add noodles, turn off heat and let noodles cook for 5 or so minutes, just until the noodles are tender. Drain and rinse until cold water.
Add noodles and sesame seeds to the bowl with the vegetable mixture and toss until everything is well combined. Serve with extra sesame seeds, scallion greens, and extra tamari.