Place chuck roast, garlic, ginger, chilies, peppercorns, cloves, cinnamon stick, cumin, coriander, salt, and water in a slow cooker. Cook on High until roast is tender, 4 to 6 hours.
Remove roast and let cool enough to handle; cut into thick slices. Strain liquid from slow cooker, discarding spices, and reserving liquid.
Preheat oven to 350 degrees F (175 degrees C).
Heat oil in a large oven-proof skillet over medium heat; cook and stir onion until brown and tender, 5 to 7 minutes.
Sprinkle chili powder over onions and cook until fragrant, about 30 seconds. Stir in tomatoes, ketchup, tomato puree, black pepper, and reserved liquid from slow cooker; cook until reduced to 3 cups, about 10 minutes.
Place sliced meat into skillet and simmer until sauce thickens, 5 to 10 minutes.
Bake in preheated oven, basting occasionally with sauce, until browned, 10 to 15 minutes.