In this salad, the Chinese use a paste of hot red pepper with sesame seeds and peanuts, it is sold in all our stores, I have brought it from China many times. But I don't like it because I don't like peanuts. If you have one, you can use it.
I suggest a more affordable option. Mix soy sauce, I have soy sauce, olive oil, table vinegar, mustard with grains, honey and chili flakes. The dressing should be sweet and spicy at the same time.