Heat the canola oil in a large saucepan or Dutch oven over medium heat.
Add the minced garlic, ginger, and thawed stir-fry vegetables.
Cook, stirring occasionally, for about 2-3 minutes until the aromatics are fragrant.
Pour in the vegetable broth, water, tamari, and rice vinegar.
Stir in the chili paste. Increase the heat to high and bring the soup to a rolling boil.
Add the noodles to the boiling soup.
Reduce the heat to medium and simmer, stirring occasionally to prevent sticking, until the noodles and vegetables are tender, about 8-10 minutes or according to package directions.
Remove the pot from the heat and stir in the chopped scallions and toasted sesame oil. Give it a final taste and adjust the seasonings if needed—a little more tamari for saltiness or chili paste for heat.
Serve immediately, garnished with extra scallions if desired.