Heat oil in large, safe skillet over medium-high heat.

Add onion. Sauté until translucent about 2 minutes.

Add wine. Boil until reduced, about 3 minutes.

Add tomatoes with juice. Bring to boil. Sprinkle fish with salt and pepper.

Add fish to skillet over tomato mixture. Reduce heat to low, cover, and simmer until fish is cooked through, about 9 minutes.

Using slotted spatula, transfer fish to plate and cover to keep warm.

Mix olives, capers, half of the oregano, and orange peel into sauce in skillet.

Increase heat to high and boil until is reduced and thickened, about 5 minutes.

Place 1 fish fillet on each plate. Pour sauce over fish, sprinkle with remaining oregano, and serve.