Combine the chicken, tomato sauce, yogurt, curry powder, onions, 1 teaspoon salt, ginger if using and green chiles if using in a bowl. Let marinate for at least 1 hour in the fridge.
Preheat the oven to 375 degrees F.
Transfer the chicken in marinade to a deep ovenproof dish; cover with foil. Bake until the chicken is thoroughly cooked, about 1 hour. (Or to prepare on the stovetop: Bring to a simmer and cook over medium heat for approximately 30 minutes.) Add salt and pepper to taste.
Garnish with chopped cilantro. Serve in a bowl as a spicy stew or with steamed rice.