Fill a 6-quart nonstick saucepan with rice, tomatoes, water, canola oil, salt, saffron, and onion. Mix together. Cover and bring to a boil over high heat. Reduce heat to medium/low. Simmer for 10 minutes. 2. Uncover and place 2 paper towels (one on top of the other) over the rice. The ends will extend outside the pot. Replace the lid tightly. Reduce heat to low and simmer for 30 minutes. 3. Turn off the heat and tilt the lid to allow the steam to escape so that the crunchy bottom does not become soggy. 4. Serve on a shallow platter, mounding the rice into a pyramid, and garnishing with the tadig.