Rinse the tofu noodles under cold water and drain well.
Slice onion, bell pepper, and cabbage thinly.
Heat cooking oil in a pan and stir-fry onion, bell pepper, and cabbage over medium heat.
When the vegetables have softened, add the tofu noodles and stir-fry together.
Add barbecue sauce and a bit of soy sauce, stirring everything together as you cook.
Finish by sprinkling sesame seeds and chopped green onions, if desired.