Boil the udon noodles according to the package instructions. Once cooked, drain and set aside.
In a large frying pan or wok, warm the canola oil over medium-high heat.
Add the minced garlic and sauté for about half a minute until fragrant.
Add the diced mushrooms, bell peppers, grated carrots, and sugar snap peas. Stir-fry for approximately 4-5 minutes until vibrant and slightly tender.
If using protein, add it now and stir well to combine.
Gently fold in the udon noodles, followed by the tamari sauce, fish sauce, sweet rice wine, and toasted sesame oil. Mix thoroughly.
Adjust seasoning with salt and black pepper as desired.
Cook for an additional 2-3 minutes, stirring continuously until heated through.
Remove from heat and sprinkle in the chopped green onions before serving hot.