Ensure avocado is ripe (soft to the touch); if avocado is too firm, ripen faster by placing in a paper bag, 1-2 days; slice avocado

Preheat oven to 400°; place fish on a sheet pan; bake 15-18 min until cooked through + hot; sprinkle with salt

Meanwhile, microwave 2 potatoes in their wrappers on high 9-11 min flipping over halfway through cook time (caution, that's a hot potato!); carefully a into each, season with salt/pep + 1 tbsp oil or butter then mash with a fork

Toast 2 buns until warm + golden; spread 2 tbsp sauce onto each bun the top with fish, avocado + a few leaves of lettuce; divide sandwiches to plates with potatoes on the side