Bring a large pot of salted water to a boil. Add the spaghetti and cook according to package directions. Drain and set aside.
Meanwhile, bring another large pot of salted water to a boil, add the sugar snap peas, return to a boil, and cook for 3 minutes, until crisp tender. Lift the sugar snap peas from the water with a slotted spoon and immerse them in a bowl of ice water. Drain.
For the dressing, whisk together the vegetable oil, rice vinegar, soy sauce, sesame oil, honey, garlic, ginger, 1 tablespoon sesame seeds, peanut butter, salt and the pepper, in a medium bowl.
Combine the spaghetti, sugar snap peas, peppers and scallions in a large bowl. Pour the dressing over the spaghetti mixture. Add the scallions and the parsley and mix again.