In a baking dish or on a rimmed baking sheet large enough to accommodate the salmon, whisk the miso, sake, mirin, honey, soy sauce, and ginger until combined. Turn the salmon in the mixture to coat and leave flesh side down. Marinate for 30 minutes at room temperature, or cover and refrigerate for up to 12 hours.
Position a rack 6 inches from the broiler element and heat the broiler on high. In a large bowl, toss the asparagus with the vegetable oil. Line a large rimmed baking sheet with foil and lightly brush with oil. Leaving a light coating of the marinade on the salmon, transfer it skin side down to one side of the sheet. Arrange the asparagus on the other side of the sheet. Sprinkle 1/2 tsp. salt over the fish and asparagus.
Broil until the salmon is browned around the edges, 2 to 4 minutes. Toss the asparagus and continue to broil until the asparagus is tender and the salmon is cooked to your liking, 3 to 5 minutes more for medium rare and 5 to 7 minutes more for medium (see this Test Kitchen post for a visual to help you gauge doneness). 1 to 2 minutes before the salmon is done, add the cherry tomatoes (if using) to the baking sheet. Use a paring knife to check for doneness; medium-rare salmon will be slightly translucent in the center, and medium salmon will be opaque but juicy.
Transfer the salmon and asparagus to a serving platter. Drizzle the sesame oil over the asparagus, sprinkle the sesame seeds over both, and serve.
nutrition information (per serving):
11, Fat Calories
100, Saturated Fat
28, Monounsaturated Fat
7, Polyunsaturated Fat
Photo: Scott Phillips