1. Bring a large pot of water to a boil and add salt. Stir in the rice and boil over moderately high heat until just tender, about 15 minutes. Drain the rice thoroughly and transfer to a large bowl. Toss the rice with a rubber spatula from time to time to cool it to room temperature.
2. In a small bowl, mix the olive oil and vinegar and season with salt and pepper. Gently fold the tomatoes, onion, cilantro and olives into the rice. Add the vinaigrette and toss well. Season with salt and pepper and serve.
Make Ahead: The rice salad can stand at room temperature for up to 1 hour.