Sauté veggies. Heat oil in a large stock pot over medium-high heat. Add onion, carrot, celery and garlic and season with salt and freshly ground black pepper. Cook, stirring occasionally, until tender. Add tomato paste and stir until it has melted in with the vegetables, about 1 minute.
Add tomatoes and spices. Add tomatoes, orange zest, chili flakes, fennel, bay leaf, saffron, and broth to the pot and stir to combine. Bring to a boil, then lower heat to a slow simmer. Cook, uncovered, stirring and breaking up tomatoes with a spoon occasionally, for 20 minutes.
Blend. Add sugar and dill and remove bay leaf. Blend until smooth with an immersion blender or using a regular blender (see notes about blending hot liquids), if desired. This is optional, if you want to have a chunkier soup, skip the blending step, add the rice to the pot and cook until rice is tender, about 8 minutes more. Taste and season with more sugar, salt, and pepper as necessary.
Cook rice. If you want to blend the soup you'll have to cook the rice separately and add it after it has been blended. To cook the rice, bring a small saucepan of water to a boil over high heat. Add a generous pinch of salt then add rice. Cook until tender, about 8 minutes then drain.
Serve. Stir cooked rice into blended soup, taste and season with more sugar, salt, and pepper as necessary. Garnish with extra chopped dill. Yum!