Cut the chicken into bite-sized pieces and then place them in a bowl. Add 1 ½ teaspoon of baking soda and 2 tablespoon of soy sauce to the chicken. Mix well to coat the chicken evenly. Cover the bowl and let the chicken rest for 10-15 minutes while you prepare the sauce and vegetables.
In a small bowl, mix the remaining 2 tablespoon of soy sauce, 1 tablespoon of rice vinegar, 2 teaspoon of sugar, and ¾ cup of chicken broth. Stir until the sugar dissolves and set aside your spicy Kung Pao sauce.
In a large skillet or wok, heat about 2 tablespoon of olive oil over medium heat. Add the minced garlic and marinated chicken and cook it for 5-7 minutes, stirring frequently, until the chicken is fully cooked and golden brown. Remove the chicken from the skillet and set aside.
In the same skillet, add a little more (about 2 tablespoons) olive oil if needed. Add the diced red bell peppers, green bell peppers, and onion. Cook them for 3-5 minutes, stirring occasionally, until the vegetables are softened. Stir in the dried whole red chili peppers and cook for another 1-2 minutes.
Pour the spicy Kung Pao sauce mixture into the skillet with the vegetables over medium-high heat. Stir well and let it simmer for 2-3 minutes. If you prefer a thicker sauce, mix 1 tablespoon of cornstarch with 2 tablespoon of water to create a slurry. Add the slurry to the skillet and turn the heat to medium-high. Cook for an additional 1-2 minutes until the sauce thickens. Add the cooked chicken and peanuts to the skillet and stir everything together, cooking for another 1-2 minutes to heat through.
Scoop some cooked whole grain rice into each serving bowl and top it with the Kung Pao chicken mixture. If you like, you can sprinkle a little bit of chopped green onions or sesame seeds over your easy Kung Pao chicken bowl before serving.