In a large bowl, mix cubed chicken with salt, chicken bouillon powder, ginger, garlic powder, onion powder, and white pepper. Let sit in the fridge for at least 30 minutes.
Mix flour, rice flour, cornstarch, salt, and water until a thick batter forms. Coat chicken thoroughly.
Heat oil to 350°F (175°C). Fry chicken in batches for 5-7 minutes until lightly golden. Remove and drain on a paper towel-lined rack.
Increase oil temperature back to 350°F. Fry chicken again for 2-3 minutes until deep golden brown and crispy.
Whisk together soy sauce, rice vinegar, orange juice, sugar, garlic, water, red pepper flakes, and cornstarch.
Heat sauce in a wok over medium-low heat until thickened. Add fried chicken and toss until evenly coated.