Recipe courtesy of Morada Bay restaurant in Islamorada.
Ginger soy vinaigrette:
Combine all ingredients in a mixing bowl and whisk until well blended, set aside. Yields 4 servings.
Place skillet over medium high heat and coat with olive oil. Season tuna generously with salt and pepper. Sear tuna in hot oil for 1 minute per side, to form a light crust.