Preheat oven to 450°.
Bake potatoes at 450° for 50 minutes or until done; cool slightly.
Reduce oven temperature to 400°.
Cut each potato in half lengthwise, and scoop out pulp, leaving a 1/4-inch-thick shell. Combine potato pulp, onions, and next 7 ingredients (through salmon) in a large bowl, stirring until blended. Spoon potato mixture into shells. Sprinkle cheese evenly over potatoes. Bake at 400° for 15 minutes or until thoroughly heated.