Heat the oil in a wide skillet on medium-high heat. When hot, add the cumin seeds and fry until lightly browned, about 10 seconds. Turn the heat down to medium and add the okra and onions, spreading them out in an even layer. Fry, stirring occasionally, for 15-20 minutes, until the pieces are browned and the okra has lost its sliminess. Add the spices and lemon juice and cook another 5 minutes, stirring gently. Serve hot, with rice and some dal (lentils) or a meat dish (or just a pork chop). Serves 4.