Bring a large pot of water to a boil, salt it, add the pasta and cook according to package directions. Drain and set aside.
While the pasta is working, in a large skillet, heat the oil over medium-high heat. Add the shiitakes and stir-fry until softened, 2 to 3 minutes; season with salt. Remove from the heat and stir in the scallions and sesame seeds. Set aside.
In a bowl, combine 2/3 cup warm water and the tamari, honey and hot sauce. Divide the sauce among 4 dipping bowls and add the ginger and garlic slices.
Toss the noodles with the shiitake mixture. To serve, pile one-quarter of the noodles on each of 4 large plates and place the dipping bowls alongside.