Preheat grill to medium heat.

Lay foil sheets out in a row on your workspace, being sure not to overlap them. Brush the middle of each with a little oil or spray with non-stick cooking spray if you want to eat the salmon skin (this will help prevent it from sticking).

Place a salmon fillet in the center of each piece of foil. Top with the long pieces of green onion, lemon slices, thyme and butter. Season with salt and pepper. To close the packet, bring the right and left sides together and fold down, sealing, and then fold up each end to seal. Repeat with remaining packets.

Place packets on upper rack of preheated grill, close, and let cook 10-12 minutes, or until they reach your desired degree of doneness.

Transfer each foil packet to a plate, carefully open, and garnish with remaining chopped green onion.