In a large Dutch oven, combine the vinegar, soy sauce, garlic, chilies, bay leaves, and peppercorns
Add chicken thighs, submerging them. Cover and refrigerate for 30 - 60 minutes
Bring the mixture to a boil over medium-high heat. Reduce to medium-low and cook, turning the thighs occasionally, until the chicken registers 170F, about 25 - 30 minutes. Adjust the heat as necessary to maintain a medium simmer
Heat the broiler with an oven rack 6 inches from the element. Line a rimmed baking sheet with foil. Remove the chicken thighs from the pot and arrange skin side up on the baking sheet. Pat dry with paper towels and set aside
Strain the cooking liquid, discarding the solids, then skim off the fat. Return 1 cup of the defatted liquid to the pot, stir in the coconut milk, and bring to a simmer over medium heat
Take the pan off the heat, stir in the cilantro, then cover and set aside
Broil the chicken until the skin is deeply browned and blackened in spots, 3 - 8 minutes (watch carefully). Serve in shallow bowls with steamed white rice, ladling the broth over the rice