Saute 1 chopped onion in 2 tablespoons vegetable oil in a saucepan over medium heat. Stir in 1 cup white rice and cook until toasted, 3 minutes. Add 1 2/3 cups water, 1 chopped plum tomato, 2 teaspoons tomato paste and 1/2 teaspoon each kosher salt and cumin; bring to a boil. Add 1 whole jalapeno. Cover; simmer 20 minutes. Remove from the heat and let sit 5 minutes. Discard the jalapeno. Top with cilantro.