1.    Preheat the oven to 350°. On a rimmed baking sheet, add the panko and toast in the oven until golden brown, about 8 minutes. Remove and set aside.

2.   In a medium saucepan, combine the red wine vinegar, sugar, ¼ cup of the salt and water and bring to a boil. Place the shallots in a medium bowl and pour the liquid over the shallots. Set aside for 30 minutes or refrigerate overnight. Strain the shallots and reserve.

3.   Fill a large bowl with ice and water and set aside. Bring a pot of salted water to a boil and add the green beans. Blanch for 30 seconds and use a slotted spoon to remove the beans and place into the bowl of ice water. Strain when the beans are completely cooled.

4.   In a large saucepan, add the tuna and cover with cold water. Place over high heat and bring to a strong simmer; as soon as liquid comes to a simmer, remove the pan from the heat and set aside for 15 minutes.

5.    In a blender, combine the mayonnaise and sherry vinegar.  Add one-quarter of the poached tuna and blend to emulsify the tuna into the mayonnaise mixture. Season with salt and pepper.

6.   Flake the remaining tuna into bite-size pieces. In a large mixing bowl, combine the flaked tuna, pickled shallots, green beans and mixed greens. Add the dressing and toss to coat. Season with salt and pepper, divide among plates, sprinkle with toasted panko and serve.