Cut salmon into small cubes. Add salmon, scallions, mayonnaise, fish sauce, garlic, lime zest, and 1/2 cup panko breadcrumbs to a food processor. Pulse until well combined. Split mixture in 4 equal portions. Form into patties and coat with remaining 1/2 cup panko. Chill for 2 hours.
While salmon patties are chilling, make your slaw. Mix together all ingredients.
For the aioli, start with mashing the avocados. Stir in remaining ingredients and season to taste. Like all other things avocado, the aioli will brown so make just before cooking your burgers.
Heat skillet over medium heat on a camp stove. Toast buns and set aside. Add oil and warm until slightly shimmery. Add salmon and cook for 3 minutes aside.
Assemble burgers by spreading aioli on the bottom bun. Add the salmon. Top with slaw and top bun. Serve immediately.
Notes
Salmon patties can be made up to two weeks ahead and frozen for transport to your campsite or beachy barbeque.