Prepare pasta according to package directions; two minutes before pasta is done, add asparagus pieces. When pasta and asparagus are done, drain. Place oil, garlic and mushrooms in a 2-quart saucepan. Sauté for 3 to 4 minutes. Add soy sauce, sesame oil, toasted sesame seeds, scallions and vinegar. Simmer for 3 to 5 minutes. Add shrimp to the sauce and cook for another 5 to 8 minutes. Toss shrimp and sauce with pasta and asparagus and serve.