2 8-ounce salmon fillets
1 bunch mustard greens, trimmed, cut crosswise into 2-inch-wide strips
Preheat oven to 350°F. Mix first 4 ingredients in small bowl. (Sauce can be prepared 2 hours ahead. Cover and let stand at room temperature.) Place potatoes in small bowl. Spoon 1 tablespoon sauce over and toss to coat. Arrange potatoes in baking pan. Bake 15 minutes.
Remove pan from oven; push potatoes to sides of pan. Spread each salmon fillet with 2 teaspoons sauce and place in center of baking pan. Bake until salmon is cooked through, about 18 minutes. Meanwhile, place greens in large skillet. Toss with 2 tablespoons sauce. Stir over medium-high until wilted, about 4 minutes. Divide salmon, greens and potatoes between 2 plates. Serve, passing remaining sauce separately.