Prepare your White Rice (to taste) according to the package's instructions.
In a medium bowl, whisk together Soy Sauce (2 teaspoon), Cooking Sherry (1/2 tablespoon) and Egg (1) for the marinade.
Cut the Boneless, Skinless Chicken Breast (8 ounce) into one-inch cubes and add to the marinade, mixing well. Set aside for at least 10 minutes while you prepare the sauce.
For the sauce, whisk together the Chicken Stock (3 tablespoon), Tomato Paste (1 tablespoon), Soy Sauce (3/4 tablespoon), Rice Vinegar (3/4 tablespoon), Hoisin Sauce (1 teaspoon), Chili Paste (1/2 teaspoon), Vegetable Oil (1 teaspoon), Granulated Sugar (3/4 tablespoon), and Corn Starch (1 teaspoon). Set aside.
In a pie plate or other deep plate, mix together Corn Starch (3/4 cup), Salt (1/4 teaspoon), and Ground Black Pepper (1/4 teaspoon). Scoop chicken out of the marinade and place in the cornstarch, turning and mixing until all pieces are coated. The mixture will be somewhat sticky.
Heat Vegetable Oil (4 tablespoon) in a large skillet over medium heat. Once hot, add the chicken pieces to the pan. Toss the chicken as it cooks, making sure that all sides of the pieces are crispy. Cook for 10-15 minutes until golden and crispy.
Remove the chicken with a slotted spoon to a plate lined with paper towels. Pour excess oil out of the pan, but do not wipe clean.
Return pan to the heat. Add Garlic (2 clove) and Crushed Red Pepper Flakes (1/4 teaspoon) to the pan and toss gently for about 20 seconds. Add sauce and allow to thicken for about 30 seconds. Turn off the heat and return chicken to the pan. Toss chicken until coated.
Serve over a bed of rice, garnished with Sesame Seeds (to taste) and Scallion (to taste). Enjoy!