Step 1Heat the broiler. Place slices of the salmon on a foil-lined baking sheet and broil until the surface of the fish turns opaque, 1 to 1 1/2 minutes on each side depending on the heat of the broiler. Remove and set aside just until the fish is cool enough to be handled. Flake the salmon using your fingers.
Step 2The salmon can be used as a filling within the onigiri or can be mixed together with the rice before forming onigiri (use half the amount of cooked rice for the basic onigiri recipe).