Turmeric, the ground spice that makes curry powder yellow, colors the rice in this main-dish salad. Parboiled rice is treated so that the starch in the grain is gelatinized, resulting in separate grains. Don't use instant, or precooked, rice in it's place.
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.