Heat a large skillet over medium heat. Add the millet. Cook, stirring frequently, for 10 minutes, until fragrant and toasted. Add the water and 1/2 teaspoon of salt. Bring to a boil, then cover, reduce heat to low, and simmer for 20 minutes, until the water is mostly absorbed. Fold in the corn, and cook, covered, for 5 minutes. Transfer the millet and corn to a large bowl and set aside to cool to room temperature.