Heat oil in a large pan or pot over medium heat, and fry cumin seeds for 1 minute or until they're aromatic.
Add in the onions and turn the heat to low. When the onions become soft and translucent, add the minced garlic and ginger, and chili if using. Cook for 1 more minute.
Add ground coriander, cumin, turmeric, and garam masala. And cook for 30 seconds.
Add a can of diced tomatoes in juice (or use fresh tomatoes if you prefer), then fill half of the same can with water and add it to the mixture. Add in the kidney beans.
Finally, add ¼ can of coconut milk, salt, and ground black pepper. Cover with a lid and simmer for 10 minutes to let the mixture cook and thicken.
Serve over steamed basmati rice, sprinkle with chopped parsley or coriander and serve with lemon wedges.