Place buttermilk in a large bowl. Season the buttermilk with salt and plenty of white pepper. Add chicken wings and combine well. Cover and leave to marinade in the refrigerator for at least 3 hours, preferably overnight.
In another bowl, mix self raising flour, potato flour and rice flour. Take the excess marinade off the chicken pieces with your hands and coat them with the flour mixture.
Heat oil in a deep fryer or a large saucepan to 140°C. Fry the chicken wings for 10-12 minutes until cooked through. Take them out on kitchen towel. Set aside. The chicken should be cooked but still white outside.
While the chicken is cooking for the first time, make the Korean Barbecue Sauce. In a saucepan mix tomato sauce, sriracha, gochujang, rice wine vinegar, ginger and sugar. Heat to boil, then simmer for a few minutes to thicken. Remove from the heat. Add and sesame oil.
Increase the oil temperature in the deep-fryer to hot - at least 190°C. Fry the chicken again for 3-5 minutes until golden and crispy. Drain the chicken on a piece of kitchen towel.
In a bowl, pour ? of the sauce over the chicken. Toss to coat.
Place the chicken in a serving dish. Pour remaining sauce, garnish with spring onion and sesame seeds. Serve with plenty of serviettes. Enjoy!