Preheat the grill to medium-high heat.

In a food processor, add the salmon fillets and pulse until coarsely chopped. Transfer to a mixing bowl and combine with breadcrumbs, mayonnaise, Dijon mustard, lemon juice, garlic powder, onion powder, salt, black pepper, and cayenne pepper if using. Mix until well combined.

Form the mixture into 4 equal patties.

Brush each patty lightly with olive oil to prevent sticking.

Grill the patties for about 4-5 minutes on each side, or until they are cooked through and have nice grill marks.

While the burgers are grilling, prepare the avocado salsa by combining the diced avocado, tomato, red onion, cilantro, lime juice, salt, and pepper in a bowl. Gently toss to combine.

Once the salmon burgers are done, serve them on buns topped with the avocado salsa.