1) Preheat the oven to 375 degrees Fahrenheit.
2) Pour the sesame seeds into a rimmed baking sheet. Toast seeds in an oven for about 10-12 minutes, or until they are a rich brown around the edges.
3) Meanwhile bring a large pot of salted water to a boil. Add the noodles and cook for 5-6 minutes, or till they are just tender. Drain them, rinse them with cold water, and drain them again.
4) In a large bowl mix together vinegar, sugar, soy sauce, garlic, oil and onions. Add noodles and toasted seeds. Toss well. then stir in the broccoli. Let dish sit for 30 minutes at room temperature before serving.