Season cubed chicken thighs with salt, garlic powder, black pepper, and ginger. Marinate for 15 minutes.
In a large bowl, whisk cornstarch, ice-cold sparkling water, AP flour, and baking powder until thick and smooth. Add chicken, coat well, and chill until ready to fry.
Sauce: Mix orange juice, vinegar, sugar, soy sauce, dark soy, and honey; set aside. For spicy mayo, combine mayo, sriracha, and a little water to thin.
Heat oil to 400°F. Fry frozen fries until golden and crispy (4–5 minutes or per package). Remove and drain.
In the same oil, fry battered chicken (stir batter before frying) in small batches until light golden and 165°F, about 5–6 minutes. Drain well.
Bring the orange sauce to a rolling boil. Add dried chilies if using, then stir in the slurry and cook until thickened. Toss in the fried chicken and fries until evenly coated.
Plate, drizzle with spicy mayo, garnish with sliced green onions, and enjoy!
