Latke Eggs Benedict

Name: Latke Eggs Benedict
Ingredients: 1 1/2 pounds russet potatoes (about 2-3 large or 3-5 medium); 1/2 medium onion; 1 large egg (lightly beaten); 2 tablespoons matzo meal or all-purpose flour; 1 teaspoon kosher salt; 1/2 teaspoon freshly ground black pepper; vegetable oil (for cooking); 3 large egg yolks; 1 tablespoon freshly squeezed lemon juice; 1/4 teaspoon kosher salt; 1/2 cup (1 stick) unsalted butter (melted); 8 large eggs (the fresher the better); splash of white vinegar; 4 oz cold smoked salmon (lox); finely chopped chives; finely diced red onion