Grate 1/2 teaspoon orange rind; squeeze 1/4 cup juice from 1 orange into a sieve over a bowl. Section remaining 2 oranges to equal 1 cup sections.
Sprinkle 1/4 teaspoon salt and 1/4 teaspoon freshly ground black pepper over fish.
Heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray.
Add fish, top side down, to pan; cook 5 minutes.
Remove fish from pan.
Add onion to pan; saut 3 minutes or until tender and lightly browned.
Add tomato, olives, orange juice, and orange rind to pan; cook for 3 minutes, stirring occasionally. Stir in 1/8 teaspoon salt and 1/4 teaspoon freshly ground black pepper. Arrange fish, browned side up, over tomato mixture in pan. Cover, reduce heat, and simmer 3 minutes.
Add orange sections; cook 1 minute or until desired degree of doneness.