Wipe and cut the chicken into 1-inch pieces.
Put the chicken into a medium-sized heavy-bottomed saucepan (Wok can be used). Cover the pan and leave it to cook in its own moisture over a low heat for about 10 minutes, stirring occasionally.
Add the tomatoes, chili powder, scallions, green chilies, and salt. Cook it uncovered over a medium heat for another 15-20 minutes or until the moisture has almost evaporated.
Heat the oil in a small skillet and cook the cumin seeds.
As they begin to turn pink, add the ginger and garlic and fry these for about 1 minute.
Add this mixture to the chicken, together with nearly all the cilantro leaves and mix them together well.
Simmer for 5-7 minutes.
Garnish the dish with the remaining cilantro leaves just before serving.