Instructions

 Melt 3 tablespoons butter in large saucepan over medium-high heat. Add garlic, 1 teaspoon thyme, ¼ teaspoon salt, and pepper flakes and cook until fragrant, about 1 minute. Add beans and their liquid and bring to simmer. Reduce heat to medium-low and simmer, stirring occasionally, until liquid is thickened and creamy, about 15 minutes. Stir in chard and cook until tender, about 5 minutes. Stir in lemon juice.
 Meanwhile, melt remaining 1 tablespoon butter in 12-inch nonstick skillet over medium heat. Add panko, lemon zest, ¼ teaspoon salt, and remaining ½ teaspoon thyme and cook, stirring frequently, until golden brown, about 2 minutes; transfer to bowl and set aside. Wipe skillet clean with paper towels.
 Sprinkle salmon with remaining ¾ teaspoon salt. Arrange salmon skin side down in now-empty skillet and cook over medium-high heat until fat is rendered and skin is crispy, about 7 minutes. Flip salmon and continue to cook until center is still translucent when checked with tip of paring knife and registers 125 degrees, about 7 minutes longer. Serve salmon over bean mixture, sprinkling panko mixture over top.