Heat the olive oil in a saucepan over medium heat. Add the onion and saute, stirring occasionally, until softened, about 10 minutes. Stir in the garlic and cook another minute or two. Add the tomatoes, herbs and spices, olives, raisins and capers and season with salt and pepper. Cook 15 minutes until thickened and no longer watery. At this point you can cool your sauce if preparing ahead of time, and continue on with step 2.
Place the fish in a baking dish coated with a little olive oil. Sprinkle a little salt over the fish, then top with the sauce. You can cover and refrigerate until ready to cook at this point.
Heat the oven to 400. Bake the fish, uncovered, until cooked through, around 20-25 minutes depending on the thickness of the fish. Serve warm with crusty bread or rice if you like.