Remove Alaska Sockeye salmon from the refrigerator 15 minutes before cooking. Heat grill to 375°F.
In a small bowl stir together the hot water, brown sugar and soy sauce. Then stir in the ginger and peanut butter until smooth. Store refrigerated for up to 2 weeks.
Cut 2 pieces of wide, heavy-duty aluminum foil about 6-inches longer than the salmon side. Stack the foil pieces (shiny side down) on a baking sheet and spray generously with cooking spray. Place the salmon, skin side down, in the middle of the foil. Fold the foil sides and ends up (1 to 2-inches) to make a shallow pan around the salmon, leaving at least a 1-inch margin around the fish. Season salmon with salt and pepper.
Carefully transfer the foil pan to the center of the preheated grill. Do not cover the salmon or close the foil over the salmon. Close grill cover and cook for 10 to 13 minutes, cooking just until fish is lightly translucent in the center – it will finish cooking from retained heat. Remove from the grill and let rest a few minutes before serving.
To serve, top salmon with sauce.