Sprinkle salmon with salt and garlic powder. Rub each fillet with half of the rosemary and leave on for cooking. Cut 1 orange in half and squeeze each half over one of the salmon fillets.
Place salmon on planks and grill salmon until it is opaque and flaky. About 12-20 minutes (depending on how thick the fillets are). Keep a spray bottle nearby for flareups because the plank will probably catch fire a little bit.
While the salmon is cooking. Slice the second orange into slices and lightly grill on both sides. It creates a whole other level of flavor for the salmon.
Serve salmon over rice, with grilled orange slices over the top and any leftover fresh rosemary you have left.