Preheat oven to 375 degrees F. Line a large baking sheet with parchment paper or coat with cooking spray.
In a small bowl, whisk together miso, sesame oil, soy sauce, ginger, and garlic until smooth.
In an even layer spread the green beans on the baking sheet. Make room in between green beans and place salmon skin side down. Brush salmon generously with miso mixture. Drizzle remaining miso mixture over green beans.
Bake for 6-10 minutes, depending on the thickness of the salmon, until salmon is opaque in the center and can flake easily. Broil for the last 1-2 minutes.
Garnish salmon and green beans with sesame seeds and scallions.
Sheet pan dinners are becoming a staple for busy weeknights. They are versatile and can be mixed and matched with different ingredients and flavor blends.