Prepare the Tuna Filling
Drain the can of tuna thoroughly and place in a medium bowl. Add the Greek yogurt, Dijon mustard, lemon juice, corn, diced red onion, dill relish or capers, garlic powder, and black pepper. Mix all ingredients until well combined and the mixture has a consistent texture. The yogurt provides creaminess while the mustard and lemon juice add tanginess.
Prepare the Wrap
Warm the burrito-sized wrap briefly in a microwave for 10-15 seconds or in a dry skillet for a few seconds on each side. This makes the wrap more pliable and easier to fold. Place the wrap on a clean, flat surface. Sprinkle the shredded mozzarella cheese evenly over the center of the wrap, leaving about a 2-inch border around the edges.
Add Filling and Fold
Spoon the tuna mixture onto the center of the wrap, on top of the cheese. Be careful not to overfill as this can make folding difficult. To fold, bring in both sides of the wrap toward the center. Then, fold the bottom edge up over the filling and continue to roll away from you, keeping the filling tight within the wrap. The goal is to create a secure package that won't come apart during cooking.
Grill the Wrap
Heat a skillet over medium heat and add a small amount of olive oil. Once hot, place the wrap seam-side down in the skillet. Cook for 3-4 minutes until golden brown, then carefully flip and cook for another 3-4 minutes on the other side. The cheese should be melted and the wrap should be crispy and golden. If needed, you can press down gently with a spatula to ensure even contact with the pan.