In a bowl, add chicken parts to buttermilk and leave for 20 minutes (longer, up to a maximum of 4 hours, will make chicken juicier).
In a shallow dish combine flour, panko, black garlic powder, smoked paprika, salt, and pepper.
Remove the chicken from buttermilk and drain. Dredge the chicken in the flour mixture.
Preheat oven to 400°F (200°C), place chicken on a parchment-lined baking sheet, spray with cooking spray and bake for 20-25 minutes, flipping halfway through, until golden and cooked through with internal temperature reaching 165°F.
Heat oil in a skillet over medium heat and fry chicken 3-4 mins on each side until crispy.
Whisk together mayonnaise, sweet chili sauce, sriracha, honey, and rice vinegar in a small bowl, adjusting seasoning to taste.
Divide out the rice, ad chicken, shredded carrot and cucumber, avocado, and green onions into 4 bowls. Bang bang sauce drizzle and top with sesame seed sprinkles.