Heat 2 tablespoons oil in a large pot over medium-high heat. Add the chopped onions and celery and saute until the vegetables are softened, about 7-8 minutes. Add minced garlic and red chili flakes and saute for 1 minute. Add tomato paste, stirring to combine, and cook for 1 minute or until the tomato paste is caramelized.
Add canned tomatoes, white wine, fish stock, olives, capers, bay leaf, and thyme to the soup. Season with salt and pepper and bring to a boil. Reduce heat to low and simmer for 30 minutes, stirring occasionally.
Meanwhile, make the garlic herb oil. Place the chopped parsley and basil in a heat safe bowl. Heat ¼ cup oil in a small pot with the smashed garlic over low heat. Continue to simmer the oil until the garlic is golden brown and softened. Remove from heat and pour the hot oil over the herbs. Let cool completely.
Add the cooked orzo and fish to the stew and increase heat to medium. Continue to simmer for 5 minutes or until the fish is cooked through. Season the stew with salt and pepper.
Portion the Sicilian style fish stew into bowl and drizzle the garlic herb oil on top. Sprinkle grated parmesan and serve with crusty bread if desired.