Salmon Cakes Eggs Benedict

Name: Salmon Cakes Eggs Benedict
Ingredients: One 15-ounce can salmon; 2 tablespoons grated onion; 3 tablespoons mayonnaise; 2 tablespoons plain breadcrumbs; 2 teaspoons Dijon mustard; Kosher salt and freshly ground black pepper; Vegetable oil for frying; 4 tablespoons unsalted butter; 3 large egg yolks; 1 tablespoon fresh lemon juice; 1 teaspoon Dijon mustard; Pinch cayenne pepper; Kosher salt; 6 large eggs; Minced fresh chives, for garnish; 1 lemon, sliced into 6 thin wedges, for garnish