Preparation

• Position a rack in the center of the oven, and heat the oven to 400°F.
• Rinse well and blot dry the chard, leaving the leaves a little moist; set aside.
• In a small bowl, stir together the mayonnaise, mustard, lemon juice, and paprika.
• Lightly spray a baking dish with the cooking oil, and then put the fish in the dish. Spread the mayonnaise mixture over the fish to cover the top and sides, and then season the fish with 1/2 tsp. salt and a generous pinch of pepper. Bake until the fish is opaque and cooked through, 12 to 14 minutes.
• Meanwhile, heat the oil and garlic in a 12-inch skillet over medium-high heat just until the garlic is fragrant and light golden, about 1 minute. Add half of the chard, the pepper flakes, 1/4 tsp. salt, and a pinch of pepper. Cook, stirring occasionally, until the chard is wilted, 3 to 4 minutes. Add the remaining chard, and continue cooking, stirring occasionally, until all the chard is wilted, about 3 minutes more.
• Arrange the fish and chard on a serving platter. Sprinkle with the chives and serve.