How to Make It
Heat 1 1/2 teaspoons oil in a large nonstick skillet over medium. Sprinkle fillets with 1/2 teaspoon salt and 1/4 teaspoon pepper. Add fillets, skin side down, to pan; cook 4 minutes on each side or until done. Remove from pan.
Place beets and 1/4 cup water in a microwave-safe bowl; cover with plastic wrap. Microwave at HIGH 6 minutes or until tender. Drain.
Whisk together remaining 2 1/2 tablespoons oil, remaining 1/4 teaspoon salt, remaining 1/4 teaspoon pepper, vinegar, rind, and juice in a small bowl. Combine beets, greens, blackberries, and mint in a large bowl. Add vinegar mixture; toss. Place 2 cups salad on each of 4 plates; top each serving with 1 fillet.