Cook the white rice in a medium pot according to package directions; keep warm.
In a medium saucepan, whisk together honey, soy sauce, 3 tablespoons water, sesame oil, rice vinegar, and red pepper flakes; bring to a boil over medium heat.
In a small bowl, whisk 2 tablespoons cornstarch with 3 tablespoons water until smooth to make a slurry.
Slowly whisk the cornstarch slurry into the boiling sauce, reduce heat to low, and simmer until slightly thickened; remove from heat once thickened.
Fill a large skillet or heavy pot with vegetable oil to a depth of 2 to 3 inches and heat over medium until the oil reaches 350°F (use a thermometer).
In a large bowl, whisk together the flour, cumin, chili powder, coriander, onion powder, salt, and black pepper. Pour the buttermilk into a separate bowl.
Working in batches, dredge the 1-inch chicken pieces first in the seasoned flour, then dip in buttermilk, then dredge again in the flour, tapping off excess.
Carefully add chicken pieces to the hot 350°F oil without overcrowding and fry 5 to 7 minutes per batch, until the internal temperature reaches 165°F; transfer to a paper towel–lined plate to drain.
When all chicken is cooked, place it in a large mixing bowl, pour the hot honey sauce over the chicken, and use tongs or a large spoon to toss until evenly coated.
Serve the coated chicken over cooked white rice and garnish with chopped green onions and toasted sesame seeds.