Grind Kashmiri chiles, cinnamon stick, cumin seeds, peppercorns, turmeric, and cloves with a mortar and pestle or electric coffee grinder until smooth. Mix in 1 tablespoon white vinegar to create a smooth paste; season with salt.

Place pork in a large glass or ceramic bowl. Add spice paste and toss until pork is evenly coated. Cover and marinate in the refrigerator, 8 hours to overnight.

When ready to cook, heat oil in a Dutch oven over medium-high heat. Add onions, garlic, and ginger; cook and stir until golden brown, about 10 minutes. Add pork and all marinade; cook, stirring frequently, until pork has firmed up, about 5 minutes. Pour in boiling water and bring to a simmer. Reduce the heat, then cover and cook until pork is tender, about 40 minutes.

Stir in vinegar and green chiles; continue to cook, uncovered, until green chiles have softened and vindaloo has thickened, about 30 more minutes. Season with salt as necessary before serving.