Prepare the vegetables: Wash all vegetables thoroughly. Remove the outer leaves of the cabbage, cut it into quarters, remove the core, and slice into thin strips. Shred the carrots, thinly slice the bell peppers, and chop the green onions, keeping the white and green parts separate.
Heat the oil: In a large wok or deep frying pan, heat the vegetable oil over medium-high heat until hot but not smoking.
Stir-fry the aromatics: Add minced garlic and ginger to the hot oil, stirring quickly for about 30 seconds until fragrant but not browned.
Add the vegetables: First, add the cabbage and the white parts of the green onions. Stir-fry for 2-3 minutes until the cabbage wilts slightly. Then add the carrots, bell peppers, and snap peas, continuing to stir-fry for another 3-4 minutes until tender-crisp.
Season the stir-fry: Pour in the soy sauce, sesame oil, and rice vinegar. If desired, add chili flakes. Stir to coat the vegetables and cook for an additional minute.
Final touches: Taste and adjust seasoning with salt and pepper. Add the green parts of the green onions just before serving.
Serve: Remove from heat and transfer to a serving platter or individual bowls. Enjoy hot, either on its own or over rice or noodles.
Notes
This stir-fry is highly adaptable; feel free to customize it with your favorite vegetables or proteins.