Trim skin from swordfish steaks. Slice them horizontally into thin slices (no thicker than 1/2 in.). Place each slice in a gallon-size resealable plastic bag and, using flat side of a mallet or the underside of a small skillet, pound until about 1/4 in. thick. Repeat with remaining slices. Season fish lightly with about 1/2 tsp. salt, stack on a plate, and chill.
In a small bowl, combine 1/2 cup panko, the currants, pine nuts, capers, lemon zest, 1 1/2 tbsp. parsley, 1/4 tsp. salt, the chile flakes, and 3 tbsp. oil.
Cut swordfish slices into pieces 3 to 4 in. wide. Set out on a work surface and brush tops with some oil, then turn slices over. Working with one slice at a time, sprinkle with 1 to 1 1/2 tbsp. panko filling. Roll up slice, tucking in sides if they're raggedy to make a neat package (some filling will fall out; don't worry about this). Skewer roll closed with toothpicks, pointing them in the same direction so the fish will be easier to turn in the pan. Repeat with remaining fish and filling.
Spread remaining 3/4 cup panko on a plate. Coat each roll with panko, pressing gently so crumbs adhere.
Heat 3 tbsp. oil in a nonstick frying pan over medium-high heat. Add swordfish rolls and cook, covered turning once, until nicely browned on top and bottom, about 5 minutes (it's okay if they're still a little pink on the sides; they'll continue to cook off the heat). Lift to a platter, twist and then pull out toothpicks. Season lightly with salt and sprinkle with remaining 1/2 tbsp. parsley. Serve with lemon wedges.
Note: Nutritional analysis is per roll.