Preheat the oven or air fryer to 400°F.
To a bowl, add the tuna, mayo, green onion, corn, black pepper, salt, red pepper flakes, yellow mustard, and parsley. Mix together well.
Add the tuna mix on top of the sliced bread. Top with shredded cheddar cheese and 3 to 4 slices of jalapeños.
Pop in the air fryer or oven for 7 to 9 minutes until the cheese is golden and bubbly on top and the bread is crispy. Broil on top for an additional 2 to 3 minutes if needed.
Take out of the oven and enjoy warm!