Mix together drained tuna, Greek yoghurt, light mayo, sriracha, mustard, minced garlic, green onions, diced jalapeño, chilli flakes, and smoked paprika
Spread the tuna mixture onto one slice of bread
Top with sliced mozzarella and place the second bread slice on top
Spray a pan with cooking spray and heat to medium
Toast the sandwich in the pan until golden brown and crispy on both sides
Cover with a lid to fully melt the cheese
Serve immediately
