Salmon with Green Beans and Smashed Potatoes

A well-thought-out cooking time makes it easier to prepare this dish on a baking sheet and reduces the waiting time. First, heat the potatoes in the microwave to make them perfectly tender with the salmon; last of all, add the green beans to keep them bright and crisp.
Preheat the oven to 425°F. Put the potatoes and 1 cup of water in a microwave-safe bowl; cover. Reheat in the microwave on high power for 6 minutes. Transfer to a plate; let cool for 5 minutes.Drizzle a baking sheet with the edges of the cooking spray. Place the fillets on one side of a baking sheet; brush with cooking spray. Place the potatoes in the middle of the baking tray. Using the flat side of a measuring cup, gently crush the potatoes. Drizzle the potatoes with butter. Combine the salt and pepper in a small bowl; sprinkle the salmon and potatoes with two-thirds of the mixture. Bake at 425 °F for 5 minutes; remove from oven.Place the beans on a baking sheet; season with the remaining salt mixture. Bake at 425 ° F for 10 minutes. Turn the grill on high; cook until the salmon is lightly browned, about 2 minutes.Combine the mayonnaise, parsley, shallots, lemon juice, and mustard in a small bowl. Serve the salmon, potatoes, and beans with the sauce and lemon wedges.