Shrimp Cakes

1 pound medium peeled, deveined raw shrimp, cut into 1/2 inch pieces
3 tablespoons unsalted butter, melted
2 large eggs, beaten
2 minced scallionsplus more, sliced, for garnish
1/2 teaspoon lemon zest, plus 1 1/2 Tbsp. fresh juice, divided
1 1/2 cups panko breadcrumbs, divided
2 1/4 teaspoons kosher salt, divided
3/4 teaspoon smoked paprika, divided
1/2 cup mayonnaise
2 teaspoons refrigerated prepared horseradish
4 tablespoons canola oil
Lemon wedges, for serving

Combine shrimp, butter, eggs, scallions, lemon zest, 3/4 cup of the panko,
1 tablespoon of the lemon juice, 1 1/2 teaspoons of the salt,
and 1/2 teaspoon of the paprika in a bowl.
Shape into 8 (3-inch) cakes.
Sprinkle remaining 3/4 cup panko on a large plate, gently transfer cakes to plate,
pressing both sides in panko.
Place cakes on a parchment paper-lined baking sheet, cover, chill 15 minutes.
Combine mayonnaise, horseradish, 1/2 teaspoon of the salt, and remaining lemon juice and paprika and set aside.
Heat 2 tablespoons of the oil in a large nonstick skillet over medium.
Cook 4 cakes 4 to 5 minutes per side.
Transfer to a plate lined with paper towels; sprinkle with 1/8 teaspoon of the salt.
Wipe skillet; repeat with remaining 2 tablespoons oil, 4 cakes, and 1/8 teaspoon salt.
Top with sliced scallions and sauce.
Serve with lemon wedges.