1/2 teaspoon cayenne pepper (or more/less depending on your preference)
1–2 Thai green chilis, minced
1 28ounce can crushed tomatoes
1 teaspoon lime juice
1/3cup chopped cilantro leaves
Combine the urad dal and kidney beans in a large pot and cover with water by at least 1 inch. Soak for at least 8 hours or overnight.
Drain and rinse beans, then return back to the pot with 8 cups water. Bring to a boil, then reduce heat to low and cook until tender, about 60 minutes. You can also cook beans in a pressure cooker for 15 minutes.
Heat the olive oil over medium heat and add the onion. Cook until onion is very soft, about 5-7 minutes. Add the ginger, garlic, cumin seeds, chili powder, garam masala, cayenne pepper and chili peppers. Cook for another 5 minutes until chilis are soft.
Add in the crushed tomatoes, cooked beans, water and cook at least another 15-20 minutes until the mixture has thickened and warmed through. Right before serving, stir in the lime juice and cilantro.