Preheat your oven or air fryer to 400°F.
In a bowl, mix together the drained tuna, mayonnaise, green onion, corn, black pepper, salt, red pepper flakes, yellow mustard, and parsley.
Spread the tuna mixture onto the sliced bread. Top with shredded cheddar cheese and 3 to 4 slices of jalapeños.
Place 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. If needed, broil for an additional 2 to 3 minutes.
Remove from the oven and enjoy your warm, delicious Jalapeño Cheddar Tuna Melt!