Cut chicken thighs into 1 inch cubes. Pat chicken dry and set aside. Grab three bowls. In the first bowl, whisk eggs. In the second bowl, add cornstarch. In the third, add flour, salt and black pepper. Toss the chicken into the cornstarch and fully coat. Next, drench chicken in egg and lastly coat in flour mixture.
Heat a large skillet over medium-high heat and add 3 tbsp oil. Carefully add the chicken to the hot skillet and let cook for about 4-5 minutes until bottoms begin to golden and crisp up. Be sure to break chicken apart if sticking together. Flip chicken over and continue to cook until golden, about 4-5 minutes. Remove chicken from skillet and set aside.
For the sauce: Mix rice wine vinegar, soy sauce, sesame oil, sambal oelek, minced garlic, jalapeno, ketchup and brown sugar.
Heat the same skillet you cooked the chicken in to medium-high heat and pour in the sauce. Let sauce slightly simmer then add the chicken back to the skillet and toss to fully coat. Serve immediately with steamed rice and sprinkle with chopped green onions (optional).