How to Make It
Oil a large steamer basket and set it in a large saucepan over 1/2 inch of simmering water. Spread the shrimp in an even layer in the basket, then cover and steam over moderately high heat for 1 minute. Scatter the squid over the shrimp, cover and steam until the squid and shrimp are just done, about 2 minutes longer. Remove the steamer basket from the pan.
Meanwhile, in a large bowl, toss the arugula with 2 tablespoons of the olive oil and season with sea salt and pepper. Mound the arugula on plates and top with the shrimp and squid. Serve the salad with lemon wedges, olive oil and sea salt.