Position a rack in the lower third of the oven and preheat to 425 degrees , or preheat a covered outdoor grill to medium-high.
Rinse the fish and pat dry with paper towels.
Zest the lemons, avoiding the bitter white pith. Reserve the zest.
Massage the fish with the juice of 1 of the zested lemons. Season the fish on both sides with salt and pepper and coat liberally in EVOO.
On a cutting board, finely chop the herbs. Add the garlic and reserved lemon zest, then chop the mixture to combine. Place the panko and breadcrumbs in a shallow dish and sprinkle the herb gremolata on top, working the mixture through the crumbs with your fingertips. Dredge the fish in the breadcrumb mixture, pressing the crumbs into the fish.
Place the fillets on a small baking sheet and bake until the breadcrumbs are golden and fish is opaque, 12 to 16 minutes, depending on thickness. Cut the remaining zested lemon into wedges. Serve fish with salad and the lemon wedges.