Combine the soy sauce, mirin and chicken stock in a small saucepan and simmer until reduced to a syrupy consistency.
Cut the salmon into long thin strips approximately 5 mm thick and thread onto bamboo skewers to form a zigzag shape.
Cook the skewers over a preheated barbecue or under a preheated grill for 1 to 2 minutes on each side.
Drizzle the skewers with teriyaki sauce and garnish with spring onion curls.
(to make spring onion curls cut spring onion into very fine slices. Place in icy cold water for a few minutes).