1. Place all marinade ingredients into a medium-sized bowl, and whisk until well blended.
2. Rinse salmon fillets in cold water, and pat dry. Sprinkle generously with salt and pepper. Place in a large ziplock bag, and pour in half of the marinade. Turn bag several times, so the marinade coats the fish.
3. Place pineapple rings in another ziplock bag, and add the rest of the marinade, shaking well to coat.
4. Marinate both the salmon and the pineapple for about an hour, turning the bags to coat two to three times.
5. Preheat an outdoor grill to medium-high heat, and lightly oil grills. Place the salmon on the grill, spaced apart, so that the fillets do not touch each other. Use a flat spatula to flip the salmon over when it’s about 60 percent cooked. (Note that a one-inch-thick piece will cook in about six to 10 minutes. After six minutes, it will be a little pink in the middle. After about 10 minutes, it will be ready.)
6. When the fish is done, remove it from the grill and let it rest. The fish will keep cooking for a few minutes after you take it off the grill.
7. Place pineapple rings on the grill, and grill about three minutes per side, until heated through and grill marks appear. Serve alongside the salmon.