In a medium Mixing Bowl, combine the 1 ½ lb boneless skinless chicken thighs cut into 3/4-inch pieces pieces with 1 tablespoon 1 tbsp soy sauce, 1 teaspoon 1 tsp cornstarch, and 1 teaspoon 1 tsp sesame oil. Toss well to coat and let marinate at room temperature for 10–15 minutes while you prep the remaining ingredients.

In a small Mixing Bowl, whisk together the 3 tablespoons 1 tbsp soy sauce, 2 tbsp rice vinegar, 1 tbsp hoisin sauce, 1 tbsp granulated sugar, 1 tsp cornstarch, and 2 tbsp water until smooth. Set aside.

Rinse peppers under cold water and pat dry. Slice off tops and bottoms, stand upright, and cut down along the inside to remove seeds and white ribs. Slice lengthwise into ½-inch strips; halve crosswise for shorter pieces. Keep sizes uniform so everything cooks evenly. If adding onion, slice it now. Measure out olive oil, salt, and pepper. Have everything ready before the pan goes on — sautéing moves fast.

Heat a large Skillet over medium heat. Add 1 tbsp olive oil per 2 peppers; warm 30–60 seconds until shimmering. Add pepper strips in a single layer — work in batches if crowded. Season with salt and pepper, stir to coat. Cook over medium heat, stirring every 2–3 minutes, for 6–10 minutes. At 6 minutes: slightly softened with snap. At 10 minutes: tender throughout with light color. For very soft peppers, cook 30–40 minutes over medium-low, stirring occasionally. Add 4 cloves garlic minced halfway through cooking. If browning too fast, add a splash of white wine or water and briefly cover to steam.

Add the remaining 1 tablespoon of 2 tbsp vegetable oil divided to the Wok over high heat. Add the 6 whole dried red chilies stemmed, seeds shaken out for less heat and stir-fry for 30 seconds until they darken slightly and become fragrant. Add the 4 cloves garlic minced, 1 tbsp fresh ginger minced, and the white parts of the 4 stalks green onions sliced, white and green parts separated; stir-fry for 30 seconds more. Add the diced 1 whole red bell pepper diced into 3/4-inch pieces and cook for 1–2 minutes until just tender-crisp.