Marinate the Chicken: Add the bite-sized chicken pieces to a bowl. Toss with dark soy sauce and cornstarch until evenly coated. Let it marinate for 15-20 minutes while you prep the other ingredients.
Make the Garlic Sauce: In a medium bowl, whisk together all the sauce ingredients until smooth. Set aside.
Fry the Chicken: Heat the oil in a large skillet or wok over medium heat. Once hot, add the chicken in batches to avoid overcrowding. Cook for a few minutes per side until golden, crispy, and cooked through. Transfer to a plate and set aside. Carefully drain excess oil, leaving about one tablespoon in the skillet.
Stir-Fry the Veggies & Chicken: Toss in the sliced bell pepper and green onions. Stir-fry for 1-2 minutes until slightly softened. Add the minced garlic and ginger to the skillet, stirring for about 30 seconds until fragrant. Return the crispy chicken to the skillet, mixing everything together.
Add the Sauce: Pour the prepared garlic sauce into the skillet, stirring well to coat the chicken and veggies. Let it simmer for 2-3 minutes, or until the sauce thickens and clings to the chicken.
Serve & Enjoy: Remove from heat and serve immediately over rice or noodles. Garnish with extra green onions if desired. Enjoy!