Crispy-Skin Fish Fillets with Wilted Escarole

Name: Crispy-Skin Fish Fillets with Wilted Escarole
Yield: 4 Servings
Ingredients: 4 6-ounce 1-inch-thick fish fillets with skin (such as salmon or black sea bass); Coarse kosher salt; 6 tablespoons olive oil, divided; 2 large garlic cloves, finely chopped; 1 large head of escarole, coarsely chopped (about 8 cups packed); 3 tablespoons Sherry wine vinegar, divided