Spread the peppercorns on a work surface and drag the bottom of a small saucepan over them, smashing them as you do this. Repeat about a dozen times until the pepper is coarsely cracked.

Sprinkle the tuna with the Creole Seasoning and then roll it in the cracked pepper, using your hands to press the pepper into and all over the loin, including the end.

Heat a large heavy dry skillet over high heat until very hot and smoking, for about 4 minutes. Add the tuna and sear for 3 minutes on one side, 3 minutes on the opposite side, the 2 minutes each on the remaining sides. Remove the tuna from the skillet and refrigerate for at least 2 hours.

Prepare the Vodka Vinaigrette.

Toss the greens with the salt, pepper, and 3/4 cup of the vinaigrette.

To serve, use a sharp knife or slicer to slice the loin of tuna into 1/4- to 1/2-inch rounds. Heap about 2 cups of the salad in the center of each of 4 dinner plates. Place 4 slices of tuna around each salad, and drizzle the remaining vinaigrette (2 tablespoons per plate) over each.