How to Make It
Stir together tuna, celery, scallions, olives, horseradish, egg, pepper, 1/3 cup of the panko, and 1/3 cup of the mayonnaise in a medium bowl to combine ingredients. Let stand 5 minutes then form into 4 equal patties. Place remaining panko in a shallow dish, and place each patty in panko, pressing to coat each side in crumbs. Set aside.
Preheat basket of an air fryer for 10 minutes at 375°F. When preheated, spray inside of basket with cooking spray, and spray both sides of 2 tuna patties liberally with cooking spray; place in basket. Cook until hot and crispy on the outside, about 15 minutes total, turning halfway through.
Meanwhile, stir together Sriracha, Dijon, lemon juice, paprika, and remaining mayonnaise in a small bowl. Serve croquettes with sauce, or make into a sandwich with your favorite bun and toppings.