To prepare rice, heat 1 teaspoon oil in a large nonstick skillet over medium heat. Add rice; cook 1 minute. Stir in turmeric and 1/2 teaspoon cumin. Add 3 1/3 cups water and 1/2 teaspoon salt; bring to a boil. Cover, reduce heat, and simmer 25 minutes or until liquid is absorbed. Remove from heat; uncover and cool to room temperature. Add corn and next 6 ingredients (corn through black beans).
To prepare dressing, heat 1 teaspoon cumin in a small nonstick skillet over low heat for 30 seconds or just until fragrant. Remove from heat. Stir in 6 tablespoons lime juice and the next 4 ingredients (lime juice through garlic). Stir into rice mixture.
To prepare topping, combine tomato, 1 tablespoon lime juice, and 1/8 teaspoon salt. Place rice mixture on a serving platter; spoon tomato topping over rice.