Starting the salmon skin side down in a cold cast-iron skillet may seem counterintuitive, but it’s the ideal technique for achieving restaurant-level crispy, crunchy skin. The fillets will release from the skillet once the skin is deeply browned, we promise. While the fish cooks, toss together a quick, punchy fennel salad featuring crunchy walnuts, briny olives, and sweet dates to serve alongside. The smooth, lemony, tahini-yogurt sauce balances out all the textures and flavors, and gets stirred up in no time.