Cook the pasta in salted water, about 8-9 minutes for al dente.  Drain, cool, toss with 1/2 TBS sesame oil and set aside.
In a small mixing bowl, add sriracha, soy sauce, minced garlic, ginger, red pepper flakes, oyster sauce and 1 TBS of the sesame oil.  Whisk and set aside.
Heat a skillet to medium high with 1 TBS sesame oil.  Add shrimp, and 1 TBS of the sauce and cook for 4-5 minutes or until shrimp are pink and cooked.  Remove from pan and set aside.
Add remaining sesame oil to skillet, then add zucchini.  Cook for 2 minutes, then add mushrooms and red bell pepper.  Continue to cook for 3-4 minutes or until peppers are slightly softened and mushrooms are cooked.  Add cooked spaghetti, green onions and remaining sauce.
continue to cook for 2-3 minutes, or until noodles are hot.   Place shrimp back in and toss until warm.  Pour into serving bowl, sprinkle with sesame seeds and cilantro.  Serve.