Heat the soy sauce, sugar, mirin, sake, spring onions and ginger in a saucepan until the mixture is boiling. Reduce the heat and simmer for 15 minutes.
Meanwhile, preheat the grill to high.
Strain the glaze mixture through a sieve into a bowl.
Thread the salmon pieces onto wooden skewers, leaving a space between each piece of salmon.
Brush the glaze onto the salmon and grill for 3-4 minutes, or until the salmon is cooked through. Baste regularly with any remaining glaze mixture.
Serve the salmon yakitori with rice and sprinkle over the flaked almonds.