Combine all the remoulade ingredients, except scallions in a bowl and stir together with a fork to help break up the capers. Mix in scallion and set aside.
For Croquettes:
Using a fork flake the salmon meat away from the skin. Discard skin.
In a medium bowl, beat egg. To the egg, add the fish fry mix, salmon, hot sauce, and 1/4 cup of remoulade sauce. Mix well to combine. Form into 8 patties.
Pour the remaining fish fry mix into a pie dish or onto a dish. Coat the patties in the remaining fish fry mix and set aside.
In a large skillet, heat a thin layer of oil over medium to medium-high heat. Without crowding pan, cook patties until golden brown, about 3 to 4 minutes per side.
Serve croquettes hot with remaining remoulade sauce.