Dice 3/4 pound wild salmon; puree half with 2 scallions. Mix with the remaining diced salmon, 1/4 cup breadcrumbs and 4 ounces chopped smoked salmon. Shape into 2 patties; make an indentation in the centers. Heat a cast-iron skillet over medium-high heat; sprinkle the skillet with salt. Cook burgers 4 to 5 minutes per side. Serve on sesame buns with sauteed spinach and mayonnaise mixed with mustard.