1. In a large saucepan of boiling water, cook the noodles for 2 to 3 minutes, or until tender. Drain and rinse in cold water. Cut into 2- to 3-inch-long pieces. Set aside.
2. In a wok or large sauté pan, heat 3 tablespoons of the canola oil and 1 tablespoon of the sesame oil over medium-high heat and stir-fry the beef strips for 2 to 3 minutes, or until browned. Remove the beef and set aside.
3. Add the onion, leek, and green onions and stir-fry for 3 to 4 minutes, or until the onions begin to soften. Add the bell peppers and cook for about 2 minutes, or until they begin to soften. Add half of the minced garlic and stir-fry about 2 minutes longer.
4. Pour the remaining 2 tablespoons canola oil into the pan and return the beef. Stir-fry for 4 to 5 minutes, or until lightly browned and cooked through.
5. Add the remaining 5 tablespoons sesame oil, the vinegar, soy sauce, tamari sauce, fish sauce, ginger, and remaining minced garlic and stir-fry for 3 to 4 minutes, tossing the ingredients and scraping the bottom of the wok to remove any browned bits.
6. Add the noodles and toss to mix and heat through. If the sauce is too thin, stir in a teaspoon of cornstarch. Divide evenly among bowls and garnish with cilantro.