1small Indian green chile or serrano chilefinely chopped
1poundgreen beansends trimmed, cut into ½-inch pieces (see Tip)
1tablespoonfresh lime juicefrom about half a lime, plus more if needed
In a medium skillet over low heat, toast the chickpea flour, stirring continuously, until the flour is golden brown, 5 to 7 minutes. Transfer the flour to a plate and let it cool. Wipe out the skillet.
In the same skillet over medium heat, warm the oil. Once the oil begins to shimmer, add the ajwain seeds and cook until they start to pop, which should be in a matter of seconds. Swirl in the turmeric and add the asafetida (if using), onion, and chile. Cook until the onion is just translucent, 3 to 4 minutes. Stir in the green beans and salt, then the toasted chickpea flour. Add ¼ cup water and mix everything together so the flour evenly coats the beans. Spread the beans out into an even layer in the pan, cover, and cook for 5 to 7 minutes, until the beans are tender and bright green and there’s a crispy layer of chickpea flour on the bottom of the pan. Once the beans are cooked, scrape up the crispy bits from the bottom of the pan and mix them into the beans. Remove from the heat and add the lime juice. Taste and add more lime juice, if needed, then give everything one last stir before serving.