Heat a large wok or sauté pan with the canola oil over medium-high heat. Add the onions and cook for 1 to 2 minutes, until the onions start to soften. Add the carrots and bok choy and cook for about 2 to 3 minutes more. Next, add the tofu, sliced scallions, and a pinch of salt and stir everything together. Cook until the tofu is heated though. Finally, add the noodles and teriyaki sauce and toss to combine everything with the sauce. Taste and add more teriyaki sauce or salt as necessary.