In glass jar with fitted lid, combine vinegar, soy sauce, 1 tsp sesame oil, maple syrup, miso, tahini, garlic, gingerroot, and red pepper flakes. Seal jar and shake well to combine. Set aside.
Preheat oven to 425 F. Line baking sheet with parchment paper. Lay asparagus on baking sheet, drizzle with remaining 2 tsp sesame oil. Toss to coat on all sides. Bake for 10 minutes. Remove from oven and keep warm.
In skillet, heat canola oil on medium-high. Season scallops with salt and pepper. Cook on one side for 2 minutes, or until golden brown and scallop releases easily from pan. Turn and cook for a further 2 minutes on other side. Add spoonful of dressing to pan to release any juices. Remove scallops to plate and drizzle with sauce. Pour remaining dressing over asparagus and use tongs to toss and coat it thoroughly. Sprinkle with sesame seeds and serve alongside scallops.