Remove the skin from the salmon and cut the flesh into small cubes, then place the cubes in a large mixing bowl.
Add the mashed avocado, chopped cilantro, yellow curry powder, and 1/2 teaspoon sea salt to the salmon; stir until evenly combined.
Stir in 4 teaspoons of the tapioca starch so the mixture holds together well.
Line a baking sheet with parchment paper. Form the salmon mixture into eight 1/4-cup patties about 1/2 inch thick and place them on the prepared sheet.
Freeze the formed patties for 20 minutes to firm them up and make coating easier.
Preheat the air fryer to 400°F (204°C) and lightly brush the basket with melted coconut oil.
Whisk the eggs in a small bowl and pour onto a shallow plate. Put the remaining 1/4 cup tapioca starch on a second shallow plate and the coconut flakes on a third shallow plate.
Working with chilled patties, dredge each patty first in tapioca starch, then dip fully in beaten egg, and finally press the top and sides into coconut flakes so the coconut adheres.
Place the coconut-coated side up in the air fryer basket. Lightly brush the tops with a little melted coconut oil.
Air-fry the cakes at 400°F for about 15 minutes, or until the exterior is golden and crispy and the interior is cooked through; use a spatula to carefully remove them if they stick.
When the cakes have about 5 minutes left, heat 2 teaspoons melted coconut oil in a large skillet over medium heat, add the arugula and spinach mix with a pinch of sea salt, and sauté, stirring constantly, for 30 seconds to 1 minute until just wilted.
Divide the wilted greens among four plates, top with the salmon cakes, garnish with extra cilantro, and serve.