Heat pan over medium to high flame, add a teaspoon of oil along with a teaspoon of shahi jeera. Wait for a minute until shahi jeera makes the little crackling sound.
Add chopped ginger and garlic to the pan, saute until ginger and garlic starts leaving out its raw smell. Add chopped onion and continue to saute it in medium to simmer flame(Be cautious and keep an eye on the pan, onions may get burnt easily. The Burnt onion flavor can spoil the whole dish). Cook onions until they become pink and translucent.
Make tomato puree, by grinding 2 tomatoes using mixer grinder. And add it to the pan.
Add red chili powder, coriander powder, turmeric powder, garam masala and a teaspoon of salt. Continue to cook until the gravy starts leaving out its raw flavor.
Add cooked rajma beans. Simmer the flame and cook again for 10 minutes. Add chopped coriander leaves and serve hot.