For the Whole30 Cocktail Sauce:
In a bowl, combine the ketchup, horseradish, lemon juice, and coconut aminos.
For the Popcorn Shrimp:
Place the arrowroot starch, cassava flour and eggs into three separate mixing bowls. Season the cassava flour with the paprika, onion powder, and a ¼ teaspoon each of salt and pepper and stir through to incorporate. Add 1 tablespoon of water to the egg and whisk vigorously until frothy.
Dredge the shrimp in the arrowroot starch, then dip into the egg wash, and finally dredge in the seasoned cassava flour.
Heat a 10-inch non-stick skillet over medium-high heat. Add the coconut oil and heat for 1 to 2 minutes, or until it reaches 350F. Shake off any excess breading from the shrimp and carefully add it to the hot oil. Cook the shrimp until it’s golden brown, 2 to 3 minutes. Flip and cook an additional 2 to 3 minutes or until cooked through. Transfer the popcorn shrimp to a plate lined with paper towel to soak up excess oil and season with a pinch of kosher salt.
Serve immediately with lemon wedges and cocktail sauce.