Rinse the dried kidney beans under cold water.Soak the beans in a large bowl of water overnight or for at least 8 hours.Drain and rinse the soaked beans.In a pressure cooker or large pot, add 4 cups of water and the soaked beans. Cook for about 20-25 minutes under pressure (or until the beans are tender). If using a pot, it will take about 45-50 minutes of simmering. Drain and set aside.
Prepare the Curry:
Heat oil in a medium saucepan over medium heat.Add cumin seeds and let them splutter.Add finely chopped onions and cook until they turn golden brown.Stir in the ginger-garlic paste and chopped green chili (if using). Cook for 1-2 minutes until fragrant.Add chopped tomatoes and cook until they break down and become a thick sauce.Mix in turmeric powder, garam masala, coriander powder, cumin powder, red chili powder, and salt. Cook for 2-3 minutes until the oil starts to separate from the mixture.Add the cooked kidney beans and 1/2 cup of water (or more if needed) to the pan. Stir well to combine.Bring the mixture to a boil, then reduce the heat and let it simmer for 10-15 minutes. This allows the flavors to meld together.Adjust salt and spices as needed.
Garnish and Serve:
Remove from heat and let the curry rest for 10 minutes to enhance the flavors.Garnish with fresh coriander leaves.Serve hot with steamed rice, roti, or naan.