In a mixing bowl, beat the eggs and lemon juice together. Stir in breadcrumbs and Parmesan cheese until the mixture becomes pasty.
Fold in the drained tuna, onion, celery, crushed red pepper, and black pepper.
Using your hands, shape the mixture into 1-inch thick patties.
Add the vegetable oil to a skillet over medium heat. Once the oil is hot, fry the patties for about 5 minutes on each side or until golden brown and cooked through. Work in batches if needed.
Serve with fresh chopped parsley as a garnish and any desired sauce.