Saute the chopped onions in the oil till transparent.Add the garlic, ginger, haldi, dhuniya and chopped tomatoes. Cover and simmer to allow the tomatoes to soften. Add the chicken and cook for another 10 minutes or until the chicken is slightly tender. Add the salt.
Take a few teaspoons of oil from this chicken into a separate frying pan. Heat and add the sliced onion, capsicum, sliced tomatoes, and garam masala. Saut this for a while till the vegetables soften lightly. To this frying pan add the cooked chicken. Mix and allow cooking for another 2-3 minutes. Serve with rice.