Preheat the air fryer to 400F and lightly grease the basket.
Place the salmon filet in the air fryer basket and cook for 12-15 minutes or until the internal temperature has reached 145F. Once the salmon is cooked, transfer it to a plate and allow it to cool for 5 minutes before shredding it in a large mixing bowl.
Add the shallot, red pepper, egg, breadcrumbs, dijon mustard, mayonnaise, lemon juice, dill, salt, and pepper to the mixing bowl with the shredded salmon and mix until all ingredients are combined.To make the salmon burgers, scoop out 1/2 cup of the mixture into patties on to a plate and press down gently with the back of a spatula or the palm of your hand to flatten the salmon patties.
Lightly grease the air fryer basket again if necessary and place the salmon patties in a single layer in the basket with about 1/2 inch of space in between them. Depending on the size of your air fryer basket, you may need to work in batches. Air fry the salmon burgers for 8-10 minutes or until the edges begin to char and the salmon burgers are warmed all the way through.
While the salmon patties cook, combine the Greek yogurt, minced chipotle pepper, lime juice, garlic powder, tajin, white vinegar, and salt in a small mixing bowl.
Assemble the burgers by spreading a generous layer of the chipotle sauce inside the bottom and top half of each brioche bun. Add the lettuce, then a salmon patty, and top with avocado and thinly sliced red onion. Enjoy!