Cut chicken into one bite size and then marinate with salt, light soy sauce, ground pepper, sesame oil and cornstarch. Mix well and set aside for at least 15 minutes.
In a large plate, mix cornstarch with all purpose flour. Then transfer the chicken cubes in to coat. Make sure each piece is well coated with flour. Do not let them sticky together. Set aside for 5 minutes.
For raw cashew, toast over slow fire until crispy.
Heat oil in wok until hot (if you insert a chopstick, there should be lots of bubbles around), fry the chicken cubes by two batches until golden brown. It takes around 1 minutes. Drain and remove extra oil.
Leave around 1 tablespoon of cooking oil in wok and fry dried chili peppers over slow fire. Continue heating for around 30 seconds, the dried chili pepper will turn dark. Place Sichuan peppercorn, ginger, garlic and spring onion, fry until aromatic. Place red onion shreds and celery, fry for 20 seconds and add a very small pinch of salt here so the vegetables can have a very basic flavor.
Place chicken cubes in, add light soy sauce and sugar, then drizzle vinegar along with the edges. Mix well. Turn off fire and then mix in cashew. If you have fresh mint, add some fresh mint leaves bring a lovely flavor.