Marinate the chicken. Add the chicken pieces to a bowl and pour the buttermilk over top. Let them soak for at least 15 minutes while you prep the rest.
Mix the coating. In a shallow dish, whisk together the cornstarch, flour, garlic powder, smoked paprika, and a pinch of salt and pepper.
Coat and fry. Lift the chicken from the buttermilk, letting the excess drip off, then dredge each piece in the flour mixture until evenly coated. Heat about 1 inch of oil in a large skillet over medium high heat. Fry the chicken in batches for 3 to 4 minutes per side, or until golden, crispy, and cooked through. Transfer to a paper towel lined plate or rack to drain.
Make the bang bang sauce. Whisk together the mayonnaise, sweet chili sauce, sriracha, honey, and rice vinegar until smooth.
Toss and assemble. Right before serving, toss the crispy chicken with the bang bang sauce.Build each bowl with a base of rice, mixed greens, cucumber, and carrot. Top with the sauced chicken and finish with cilantro and a squeeze of lime.