Heat a deep cast iron pan over medium heat with 1 inch of oil to about 265 degrees Fahrenheit.
In the meantime, whisk the flour, water, egg, cornstarch, baking powder, salt, pepper, garlic powder, ginger powder and paprika together in a large bowl.
Add the chicken to the batter and once the oil is hot, lightly drain 6-8 pieces from the batter and fry in the oil for 3-4 minutes or until light and golden.
Drain the chicken from the oil on a plate with a paper towel and repeat the cooking process with the remaining chicken.
To make the sauce, heat the sesame oil in a saucepan over medium heat - then add the ginger and cool for 30 seconds then add the remaining sauce ingredients and stir and cook until the sauce becomes thick, about 5 minutes.
Lay the chicken out on a cooling rack and brush the sauce overtop.
Garnish with freshly chopped green onions and sesame seeds then serve.