In a medium bowl, whisk together soy sauce, vinegar, brown sugar, crushed garlic, peppercorns, and bay leaves until sugar dissolves and marinade is smooth (about 1 minute).

Place chicken wings in the bowl, toss thoroughly to coat each piece, then cover and refrigerate for at least 30 minutes (or up to 4 hours) for deep, tangy flavor.

Heat 2 tablespoons of oil in a large skillet over medium-high heat until shimmering, about 1–2 minutes.

Add wings in a single layer, cooking 4–5 minutes per side until golden brown and crisp.

Pour in the reserved marinade and ¼ cup water, bring to a boil, then reduce heat to low, cover, and simmer 15–20 minutes until wings are tender.

Remove the lid, increase heat to medium-high, and cook 3–5 more minutes until the glaze thickens.

Transfer wings to a serving platter, sprinkle optional chili flakes and chopped green onions, then serve.