In a small saucepan, heat oil over medium-high heat. Add scallions and cook until softened, about three minutes. Add garlic and ginger and cook for one minute. Add vinegar, miso, soy sauce and brown sugar and cook for about five minutes.

Place salmon in a bowl and pour about three-fourths of sauce (reserving the rest for later) onto salmon, coating all pieces. Marinate for about 30 minutes and up to two hours. Thread about two to three pieces of salmon onto each skewer.

Preheat the oven to broil. Place skewers onto a baking rack or onto a foil-lined baking sheet. Cook for about two minutes, six inches underneath the broiling burner. Turn salmon over and cook for another three minutes, or until lightly browned. Alternatively, grill salmon on gas or charcoal grill, turning to cook on all sides.

Brush salmon with some of the remaining sauce (serve some alongside the skewers) and sprinkle with sesame seeds.