Preheat the oven to 400ºF (205ºC) and line a baking sheet with parchment paper.
In a small bowl, mix together the tuna, mayonnaise, and green onion. Season with salt and pepper.
Cut the jalapenos in half lengthwise and remove the seeds. Stuff each half with the tuna mixture, about one tablespoon per half. Top with mozzarella cheese.
Place the stuffed jalapenos on the baking sheet. Bake in the oven for 13 to 15 minutes or until the cheese has melted and is golden brown. Enjoy!
