Step 1
Heat 2 Tbsp. extra-virgin olive oil in a large skillet over medium-high. Add ⅓ cup panko, season with kosher salt, and cook, stirring occasionally, until golden brown and crisp, about 3 minutes. Transfer to a small bowl. Wipe out skillet and reserve.
Step 2
Working with 1 large skinless, boneless chicken breast at a time (2 total), hold a knife parallel to cutting board and cut in half, slicing along a long side to make 4 thin cutlets (if still thick, lightly pound between sheets of plastic wrap until no more than ½” thick). Season cutlets with salt and freshly ground pepper. Place 2 Tbsp. all-purpose flour in a shallow bowl. Add cutlets and turn to coat.
Step 3
Heat 3 Tbsp. extra-virgin olive oil in reserved skillet over medium-high. Working in 2 batches, cook chicken until golden underneath, about 3 minutes. Turn over and cook on other side until cooked through, 1–2 minutes. Transfer to a cutting board.
Step 4
Heat 2 Tbsp. extra-virgin olive oil in skillet over medium. Add 1 lemon, thinly sliced, seeds removed, 3 garlic cloves, thinly sliced, and 3 Tbsp. coarsely chopped drained capers; season with salt. Cook, stirring often, until slightly softened, about 3 minutes. Add 3 Tbsp. water and cook, scraping up any browned bits stuck to bottom of pan, until combined, 1–2 minutes. Remove from heat.
Step 5
Place 1 head of radicchio, cut into 2″-thick wedges, and most of ¼ cup parsley leaves with tender stems in a large bowl. Drizzle generously with extra-virgin olive oil and add pan sauce; toss to coat and separate radicchio.
Step 6
Cut each cutlet into 3 or 4 pieces; add to salad and toss to combine. Transfer to a platter. Top with panko and remaining parsley; season with pepper.
