Once the marinating time is up, line a second baking sheet with parchment paper. Pat the salmon pieces on the prepared baking sheet. Sprinkle sesame seeds on top. Place the baking sheet on the top rack in the upper third of the oven, with the squash continuing to cook on the lower rack, then increase the heat to broil on 550℉. Broil for 5 minutes, then reduce the heat back to 425℉.
Cook the salmon and squash for an additional 6 minutes for medium-rare salmon (about 130℉ internal temperature), or an additional 8 minutes for medium-well doneness (about 140℉).