Cut chicken breast into 1" pieces, and place in a glass dish. Sprinkle with cornstarch, then add in the spice mixture, and toss to evenly cover. Place in the refrigerator for about 30 minutes.
Next, on medium heat, heat oil in a braising pan and add chicken. Cook, for about 5 minutes, turning frequently. Next add the onion and the garlic, and cook for an additional 5 minutes.
Pour in the water, and allow it to come to a boil, then add the tamarind juice and the coconut milk.
Toss in the tomatoes and the jalapeno pepper. Add the pod mixture.
Reduce heat, cover, and cook for an additional 10 minutes.
Serve with naan bread and basmati rice.