Cook the spaghetti according to the package directions and drain. Combine ½ tablespoon of the sesame oil with 1 tablespoon of the soy sauce. Toss warm spaghetti with this mixture and set aside. In a wok or a large nonstick skillet, add ½ tablespoon vegetable oil over medium-high heat until hot. Add the ginger, garlic and ¼ cup scallions, stirring constantly, and cook for about 1 minute until very fragrant. Stir in snow pea pots, sweet bell peppers, and mushrooms, and cook for about 3 minutes until vegetables become soft but still crispy. Meanwhile whisk together remaining ½ tablespoon sesame oil, 1 tablespoon soy sauce, rice vinegar, dry mustard and hot chili oil until well blended. Pour over the vegetables, stirring constantly, and cook for another 1 minute until heated through and weel coated. Season with more soy sauce, rice vinegar, hot chili oil, sesame oil if needed. Remove the wok or skillet from the heat, and stir in cilantro and scallions until well combined. Serve warm, at room temperature or chilled.