Preheat outdoor or indoor grill OR oven to 375 degrees. On a plate, combine flour and salt and pepper to taste; dredge fish.
Heat 1 tablespoon of the olive oil in a skillet over medium-high heat; brown fish fillets well on both sides then arrange them on a sheet of heavy-duty aluminum foil wrap; fold the edges of the foil up about 1 inch to create a “dish” (or use a small square baking dish if using the oven).
Add remaining oil to the skillet; cook onion and garlic till soft. Add tomatoes, spices and additional salt and pepper to taste. Bring to a boil then reduce heat and simmer, uncovered, for about 10 minutes, to
reduce the sauce.
Pour sauce over fish, sprinkle with Feta cheese and grill/bake, uncovered, for 15 minutes or until fish flakes easily when tested with a fork.