Peel and section oranges over a bowl, reserving 2 tablespoons juice. Thinly slice fennel bulb; chop 1 teaspoon fronds. Discard stalks. Place orange sections and sliced fennel in a medium bowl. Combine reserved juice, fronds, 1 tablespoon olive oil, 1/4 teaspoon salt, and 1/4 teaspoon freshly ground black pepper in a small bowl, stirring with a whisk. Drizzle juice mixture over fennel mixture; toss well to coat. Heat remaining 1 tablespoon olive oil in a large nonstick skillet over medium-high heat. Sprinkle fish evenly with 1/2 teaspoon salt, 1/4 teaspoon freshly ground black pepper, and thyme. Add fish to pan; cook 4 minutes on each side or until desired degree of doneness. Serve with fennel salad.