Cube chicken and set aside.
Mix salt, pepper, cornstarch and flour in a medium bowl and whisk to combine.
Add egg, water and oil until the consistency is like a batter.. Add chicken to the batter and refrigerate for 30 minutes.
Heat oil in deep fryer to 350. Add chicken and fry until golden brown (or about 5 minutes). Remove chicken and add to a paper towel-lined plate.
Make sauce by adding oil to a pot and cooking on medium-high heat. Add red pepper flakes, ginger and garlic and cook for about 30 seconds.
Add brown sugar and orange juice and stir to combine. Mix in vinegar and soy sauce until combined.
In a separate bowl, mix cornstarch and water. Add to the sauce pan and stir. Cook until sauce thickens.
Add chicken and stir to coat. Top with sesame oil and sesame seeds if desired. Serve over rice or noodles.