Preheat the oven to 450 degrees F and set a wire rack on a rimmed baking sheet; coat the rack with cooking spray. Combine the mayonnaise, lemon zest and 1 tablespoon lemon juice in a shallow dish; season with salt and pepper. Combine the panko, parsley and capers in another shallow dish; season with salt and pepper.
Pat the fish dry with paper towels. Dip the fish in the mayonnaise mixture, flesh-side down, then dredge in the panko mixture, pressing to coat. Transfer to the prepared rack, crumb-side up. Coat the fish with cooking spray. Bake until golden and crisp, about 15 minutes.
Meanwhile, whisk the remaining lemon juice with the mustard in a large bowl. Gradually whisk in the olive oil until smooth; season with salt and pepper. Add the mesclun greens, beets, cucumber and apple and toss well to coat; season with salt and pepper. Serve with the fish and lemon wedges.
Photographs by Charles Masters
Recipe courtesy of Food Network Magazine