Start by combining the sliced chicken thighs with water, cornstarch, and oyster sauce in a bowl. Let it marinate for about 20 minutes. This process, called "velveting," ensures that your chicken becomes wonderfully tender.

While your chicken is marinating, gather all the ingredients. Slice the ginger and garlic, chop the vegetables, and have your spices ready. This preparation saves time and helps everything come together quickly.

In a large skillet or wok, heat the neutral oil over medium-high heat. You'll want it hot enough to create a nice sear but not so hot that it smokes fiercely.

Add the marinated chicken to the skillet. Stir-fry for about 5-7 minutes until the chicken is browned and cooked through. Don't rush this; it’s crucial for developing flavor.

Throw in the ginger, garlic, and dried red chilies. Stir them with the chicken for another minute. The sizzling sound and aroma will instantly make you hungry.

Pour in the Shaoxing wine and soy sauce, stirring to coat the chicken evenly. Add in the rinsed fermented black beans and chili oil, which will give your dish a beautiful depth of flavor.

Now add leeks, bell peppers, and long green hot peppers to the mix. Stir-fry these for around 2-3 minutes. You'll appreciate the contrast of textures and colors in your pan.

Add hot water, sugar, rice vinegar, and white pepper, and stir everything together. This step balances out the flavors and brings harmony to the dish.

As the sauce thickens, drizzle in the toasted sesame oil. It adds that nutty richness that takes the dish to another level of umami.

Serve your finished Hunan Chicken hot, garnished with scallions if you desire. Don't forget to have that jasmine rice ready to soak up all that glorious sauce.