Soba noodles are made of buckwheat flour and have a toasty, nutty flavor. You can sub whole-wheat linguine if you can't find them.
Prepare soba noodles according to package directions. Drain; rinse under cold water. Drain.
Combine soy sauce, vinegar, oil, and hoisin sauce in a large bowl, stirring with a whisk. Add noodles; toss. Sprinkle with green onions and sesame seeds.