Add all marinade ingredients to a medium bowl and whisk to combine.
Place salmon pieces into a large mixing bowl and pour marinade over meat. Stir to combine, cover and refrigerate overnight, stirring once or twice while marinating. Allow marinating for at least 6-8 hours.
Skewer marinated salmon along with the sliced onion and pineapple, alternating them on the skewer.
Grill kebabs over med/high heat for about 8-10 min or until the desired doneness is reached, rotating every 2-3 min for even grilling.
Remove kebobs from the grill and let them rest at least 5 min before serving.