In a bowl, combine chicken, soy sauce, and Chinese cooking wine. Marinate in the refrigerator for about 20 to 30 minutes. Drain chicken, discarding liquid.
In a bowl, combine egg whites and cornstarch. Whisk together until well-blended and frothy. Add chicken and mix to fully coat.
In a thick-bottomed, deep pan over medium heat, heat oil. Add chicken pieces and stir to prevent them from lumping together. Deep-fry for about 5 to 6 minutes or until golden.
With a slotted spoon, remove from heat and drain on a wire rack.
In a pan, heat about 1 tablespoon oil. Add garlic and ginger and cook until softened.
In a bowl, combine calamansi juice, 2 tablespoons soy sauce, 1 tablespoon Chinese cooking wine, sesame oil, brown sugar, and red chili flakes.
Add the sauce mixture to the pan and cook, stirring regularly, until sugar is dissolved.
In a bowl, combine cornstarch and water and stir until smooth. Slowly add to calamansi sauce, whisking vigorously to prevent lumps. Continue to cook for about 1 to 2 minutes or until thickened.
Add fried chicken pieces and toss to coat with the sauce fully.
Place on a serving platter and garnish with sesame seeds and green onions. Serve hot.