Cook sweet potato noodles in boiling water according to package directions. This should take around 10-15 minutes.
While the noodles are cooking, wash your vegetables. Then, slice you bell pepper, onion, and shiitake mushrooms.
Heat pan on medium heat. Once the pan is hot, add oil and your sliced onions. Then, add ½ teaspoon salt. Mix together for 2 minutes.
Then, add your bell pepper and mushrooms. Add remaining ½ teaspoon of salt and saute for 2-3 minutes.
Lastly, add your spinach and cook for 1 more minute until the spinach is slightly wilted.
Keep your vegetables in the pan while you are cooking the noodles.
After 15 minutes of cooking, give a taste test for your noodles, they should be soft. Rinse noodles under running water and strain.
Put your vegetables and noodles in a large bowl. Mix with soy sauce, dark soy sauce, grated, garlic, sesame oil, fish sauce (optional), black pepper and sesame seeds. Mix everything well and give it a taste to ensure it is savory enough for you.