Whisk together marinade ingredients and pour over fish; allow to marinate for thirty minutes.
Drain marinade and reserve.
Place reserved marinade into a small saucepan and reduce to a syrupy consistency over low heat, stirring constantly (it should coat the back of a teaspoon when ready).
Grill salmon over hot coals 3-4 minutes per side, or done as you like.
Serve salmon drizzled with sauce reduction and garnished with sliced scallions.