Heat a medium to a large skillet over high heat. Once the pan is very hot, add the oil and turn the heat down to medium. Add the onion, red bell pepper, green bell pepper, and broccoli. Cook until the vegetables are just starting to soften, about 1 to 2 minutes, stirring frequently.
Stir in the garlic, tamari sauce, rice vinegar, keto brown sugar, ginger, and white pepper, and cook for 30 seconds, stirring constantly.
Add the Palmini linguine and cook for 2 minutes, stirring frequently. Remove from the heat.
Top with the toasted sesame oil, scallion, and sesame seeds.
Serve.