Fish Milanese with Cucumber Ceviche

Name: Fish Milanese with Cucumber Ceviche
Ingredients: 4 cups cilantro; 1 1-inch piece ginger, peeled, finely grated; 1/2 cup neutral oil (such as sunflower or canola); 3 tablespoons fresh lime juice; 4 cups panko (Japanese breadcrumbs); 4 large egg yolks; 2 cups buttermilk; 1 cup cornstarch; 4 skinless, boneless gray sole or flounder fillets (about 1 1/2 pounds total); 3 medium Persian cucumbers, cut into small pieces; 1 medium fennel bulb, cut into small pieces; 1/2 small red onion, very thinly sliced; 1/2 serrano chile, thinly sliced