Instructions

• Prepare a charcoal or gas grill fire for indirect cooking over medium heat (350°F to 375°F).
• Rinse the fillets and pat dry. Brush the skin side of the fillets lightly with oil. Put the fillets on a large rimmed baking sheet, skin side down, and season with the chile, salt, and pepper. Divide the garlic among the fillets and drizzle each with 1 tsp. of the oil. Let marinate while preparing the onions.
• Clean and oil the grill. Lightly oil the onions and place them on the hot side of the grill, turning occasionally until charred on all sides, about 15 minutes. Transfer to the cooler part of the grill and cook until softened and a knife pierced into the center comes out easily, about 30 minutes more.
• Transfer to a cutting board. When cool enough to handle, halve the onions lengthwise and thinly slice. Put the onions in a medium bowl and drizzle with half of the lemon juice and season to taste with salt and pepper. Toss with the chives and set aside.
• Prepare the grill for direct grilling on medium heat (350°F to 375°F). Clean and oil the grill.
• Place the fish, skin side down, on the grill. Cover the grill and cook, without disturbing, until just cooked through, about 8 minutes. The flesh should flake easily with a fork.
• Using a long metal or fish spatula, transfer each fillet to a serving plate. Garnish each with a sprinkling of coarse sea salt, some parsley, a drizzle of the remaining lemon juice, and 1 tsp. of olive oil. Serve with the grilled onions and lemon wedges.