Cut the chicken thighs into bite-sized pieces.
In a wide shallow bowl, whisk together the flour, cornstarch, a sprinkle of salt, and a sprinkle of black pepper to taste.
In a small deep bowl, whisk together the eggs, a sprinkle of salt, and a sprinkle of black pepper to taste.
Dip a few chicken pieces at a time first into the wet batter, letting any excess drip off, and then into the dry mixture, shaking off any excess. Set them on a plate and finish breading all the chicken.
Over medium-high heat, add soy sauce, orange juice, rice vinegar, brown sugar, sesame oil, minced garlic, minced ginger, and red pepper flakes to a pot. Bring to a simmer and then pour in the cornstarch slurry (water and cornstarch whisked together) to thicken into a glaze. Once it thickens, remove from heat and transfer to a large bowl. Set aside.
Heat vegetable oil to 350°F in a frying pan. Drop the breaded chicken in, making sure not to overcrowd. Fry in two batches. Once golden, about 4 minutes, remove from the oil and drain on a paper towel.
Toss the chicken in the glaze.
Garnish with green onions and sesame seeds, and enjoy with rice or noodles!