Heat the vegetable oil in the skillet until shimmering. Add the okra and cook over moderately high heat, shaking the pan occasionally, until beginning to brown, about 3 minutes. Add the tomato paste, lemon juice and ground cumin and stir well to coat the okra. Continue cooking until the okra is tender but firm and nicely glazed, about 1 more minute. Season with salt and pepper and serve at once.