Turn on the oven to 200ºC (392ºF).
Drain the tuna.
Shred the cheddar.
Mix tuna, red onion, cream cheese, and mayo.
Add half the shredded cheddar, paprika, tabasco, sea salt, and pepper to the tuna.
Place the tuna mixture in a baking dish.
Top with the remaining shredded cheese.
Bake for approximately 15 minutes until the cheese is melted and golden.
Sprinkle with chopped green onion.
Remove from the oven and serve on a platter with cucumber, celery, carrots, crackers, or tortilla chips.