How to Make It
In a medium bowl, cover the coconut with water and let stand at room temperature until softened, 45 minutes. Drain and transfer to a food processor. Add the jalapeño, yogurt and ginger and pulse until a coarse paste forms.
In a small skillet, heat 2 teaspoons of the oil. Add the curry leaves and mustard seeds and cook over moderate heat, stirring frequently, until the seeds start to pop, about 30 seconds. Transfer to the food processor with the coconut mixture and pulse until just combined. Season with salt and pepper.
In a large cast-iron skillet, heat 1 tablespoon of the oil. Add half of the green beans, season with salt and pepper and cook over high heat, stirring occasionally, until tender and lightly charred, 2 to 3 minutes. Transfer to a large bowl. Repeat with the remaining oil and green beans. Toss the charred beans with the coconut mixture and cilantro, transfer to a platter and serve.