Begin by cutting the chicken thighs into 1.5-inch cubes. In a medium bowl, combine the chicken with cornstarch, soy sauce, baking soda, and a drizzle of oil. Let marinate for 15-30 minutes.

Prepare the sauce by whisking together soy sauce, oyster sauce, rice vinegar, minced garlic, freshly grated ginger, and sugar in a bowl. Mix until the sugar is fully dissolved.

Heat a large non-stick pan or wok over medium-high heat and add vegetable oil. Once hot, add marinated chicken, spreading out for even cooking. Fry for about 5-6 minutes until golden brown.

In the same pan, add more oil if needed and toss in dried chilies, chopped green onions, and peanuts. Sauté for about 15 seconds until fragrant. Then, add diced red bell pepper, stir-frying for another 30 seconds until tender-crisp.

Return the cooked chicken to the pan, pour the prepared sauce over everything, and stir well. Stir-fry for another 30 seconds until sauce thickens and coats the chicken and veggies.