Bring a large saucepan of water to a boil. Add the rice and a generous pinch of salt and boil until barely al dente, about 15 minutes. Drain, shaking out the excess water. Return the rice to the pan. Cover tightly and cook over very low heat for 10 minutes. Fluff the rice with a fork, cover and keep warm.

In a large, deep nonstick skillet, heat the oil. Add the mustard seeds and cook over moderately high heat until they begin to pop, about 2 minutes. Add the onion, bay leaves, and turmeric and cook, stirring occasionally, until the onion is lightly browned, about 6 minutes. Add the cashews and chickpeas and cook, stirring occasionally, until lightly browned, about 3 minutes. Add the rice and lemon juice and toss to combine. Discard the bay leaves. Serve hot or warm.