Preparation

Prepare the fish

• Brush both sides of the fish with olive oil and season with salt, black pepper, and a sprinkle of oregano. Set aside while you prepare the horta and tomatoes.

Prepare the horta

• Bring a large pot of lightly salted water to a boil over high heat. Prepare the greens by cutting out the core if you are using escarole, cutting off the lower stems for chard, or removing the stems if you’re using kale.
• Coarsely chop the greens, add them to a big bowl of cold water, and swish around to remove the sand and dirt.
• When the water comes to a boil, add the greens and cook for about 5 minutes, or until tender. While greens are cooking, combine the lemon juice and zest with the garlic in a large bowl. Slowly whisk in the olive oil, add the crushed red pepper flakes, and season to taste with salt and pepper. Thoroughly drain the greens and set them aside to cool slightly.
• When the greens are cool enough to handle, squeeze any remaining water from them and add them to the lemony vinaigrette. Mix well to thoroughly coat the greens and hold at room temperature until ready to serve.

Prepare the tomatoes

• In a small nonreactive bowl, toss the diced tomatoes with the shallots, olive oil, vinegar, and herbs. Season to taste with salt and black pepper.

Grill the fish and serve

• Heat a gas grill or start the coals for a charcoal grill 30 minutes before cooking the fish. When the grill is hot, oil the grate and place the fish, skin side down, on the medium-hot part of the grill. Cook for about 5 minutes and lift the edge of the fish with a spatula to see if it is ready to turn—the skin should be crisp and the fish will release easily from the grill. Rub the grate with a bit more oil and turn the fish over to finish cooking, about 3 minutes. The fish can also be sautéed in a hot pan with olive oil using the same technique.
• Put the horta on a serving platter and arrange the fish on top. Spoon the tomatoes over the fillets and sprinkle lightly with coarse sea salt. Serve with lemon wedges.