Put the vegetable and sesame oils in a large pot over medium heat. When they’re hot, add the garlic. As soon as it begins to sizzle, add the chiles, carrot, celery, daikon, and cabbage; sprinkle lightly with salt and pepper. Cook, stirring occasionally, until the vegetables begin to soften, 3 to 5 minutes. Add the stock and soy sauce and bring to a boil.
Adjust the heat so the soup bubbles gently. Cook until all the vegetables are as crisp or tender as you like, anywhere from 10 to 30 minutes. Taste and adjust the seasoning, adding more soy sauce if you’d like. Sprinkle with the scallions and sesame seeds, drizzle with a little sesame oil, and serve.