Pat the fish dry with papers towels. Lay the fish on a baking sheet lined with parchment paper. Salt and pepper both sides of the fish. Sprinkle fish with garlic, paprika, and cinnamon. Arrange sliced onion and cut tomatoes over the fish. Drizzle olive oil and lemon juice over the spiced fish and onion and tomatoes. Place in the oven and bake until the fish is opaque and pulls apart easily with a fork, about 30 minutes. Serve hot with chopped parsley garnish.