To make the tomato sauce: over low heat heat oil in a saucepan and then add the onion cook, stirring for 10 minutes or until soft.
Add garlic and continue stirring for 30 seconds.
Stir in cumin and turmeric for another 30 seconds.
Stir in tomatoes, cayenne, salt and pepper.
Bring mixture to a boil; reduce to low and cook for 30 minutes or until tomatoes are soft, stirring occasionally.
Stir in tomato paste, if desired (the tomato paste will help give the sauce the bright red color).
***The sauce can be prepared one day ahead, covered and refrigerated.***.
With a meat pounder or rolling pin and chicken breasts between waxed paper, pound the chicken to a thickness of 1/4 inch (can be prepared 4 hours ahead, wrapped tightly and refrigerated, bringing to room temperature before continuing).
Preheat oven to 275-degrees F.
Reheat sauce over low heat and add minced cilantro, adjust seasoning if desired; cover and keep warm.
Heat skillet over high heat.
Pat chicken dry and sprinkle with salt and pepper and brush with oil.
Cook chicken pieces 1-2 minutes per side or until firm to touch.
Transfer chicken to oven-proof platter; cover and keep warm in oven while preparing remainder of chicken.
Divide sauce among plates and top with chicken, garnishing with cilantro if desired.