In a medium mixing bowl, combine salmon, egg, onion, parsley, breadcrumbs, mustard, salt, and pepper. Form into 8 small patties.
Pour olive oil in a skillet over medium heat. Add salmon patties and cook until golden-brown and crispy on the outside, about 3- 4 minutes on each side.
Place a patty on each roll and top with lettuce, tomato, and onion, or condiments of choice.