Place the frozen seafood in a large bowl. Fill the bowl with cool water. Allow to defrost for about 5 minutes, stirring gently to separate pieces, and replacing the water once during the defrosting process. Place the defrosted seafood on a clean kitchen towel or on paper towels to dry.
Melt the butter in a very large skillet over medium-high heat. When foaming subsides, add the seafood, kosher salt, minced garlic, paprika, and red pepper flakes. Stir-fry just until opaque, about 5 minutes.
Transfer the sauteed seafood to a serving platter, spooning the pan juices on top. Squeeze lemon juice on top of the seafood saute and garnish with chopped parsley. Serve immediately.