Wash duck pieces with lime juice and water, trimming off excess fat and skin. Drain well.
Season duck with tomato, onion, hot pepper, geera, amchar masala, salt, green seasoning, garlic, black pepper, and shado beni. Marinate 1–2 hours or overnight.
In a heavy pot over high heat, warm oil. Mix curry powder with ¼ cup water into a paste. Add sliced onion and curry paste to hot oil. Cook on medium for 5 minutes until fragrant and thick.
Add seasoned duck and stir to coat with curry base. Cover and simmer 35 minutes until juices are released.
Remove lid and increase heat to reduce liquid, stirring to prevent sticking.
Add 2 cups water, bring to gentle boil, cover, and simmer another 35 minutes until duck is tender and sauce has thickened. Adjust salt if needed.
Serve hot with dhalpourie, roti, rice, or your favorite starch.