In a medium mixing bowl, combine the mayonnaise, minced capers, and fresh lemon juice. Mix until well blended. Taste and adjust seasoning if necessary. Set aside as you prepare the salmon.
Sprinkle ½ teaspoon of kosher salt over the salmon fillets evenly. This simple step enhances the flavor of the fish.
Dip each salmon piece into the lightly beaten egg whites, allowing any excess to drip off. Next, coat the salmon in seasoned panko, pressing gently to ensure the crumbs adhere well to the fish.
Preheat your air fryer to 400°F (200°C) for about 5 minutes. This step is crucial for achieving that perfect crispiness.
Lightly spray the basket of the air fryer with olive oil. Place the coated salmon fillets in the basket in a single layer, making sure they aren’t overcrowded. Spray the tops with olive oil. Cook for about 8-10 minutes, flipping halfway through, until the salmon is golden and crispy.
To assemble your sandwich, spread a generous amount of the caper-mayonnaise sauce on the bottom half of each bun. Place a crispy salmon fillet on top, followed by a butter lettuce leaf. Top it off with the other half of the bun.
Serve these delicious sandwiches immediately with your favorite side, such as sweet potato fries or a fresh salad. Enjoy the explosion of flavors and textures!