Wash and dry the lettuce and tear into bite-size pieces.

Line a large plastic bag with a sheet of paper toweling. Add the greens and place another sheet on top of them. Close and refrigerate.

In a medium saucepan of lightly salted boiling water, cook the fresh lima beans for 10 to 15 minutes until tender. (If using frozen beans, cook for 1 to 2 minutes.) Drain, cool under cold water, and drain again. Set aside.

Rub the duck skin with the thyme. Season with salt and pepper, and set aside.

In a large skillet, heat 2 tablespoons of the oil over medium heat. Add the peppers and, tossing occasionally, cook until wilted, about 10 minutes, Using a slotted spoon, remove the peppers to a bowl and set aside.

Raise the heat to high. When the skillet begins to smoke, add the duck breasts, skin side down. Cook until the skin is golden, about 4 minutes. Turn and sear for 3 more minutes until the duck breasts are rare. (Magrets are best served rare; for medium rare, cook about 2 minutes longer.) Remove from the pan and reserve on a warm plate.

In a large bowl, whisk together the vinegar with salt and pepper to taste. Gradually whisk in the remaining 6 tablespoons oil. Add the greens and toss to coat. Divide the greens among 4 serving plates and sprinkle with the lima beans and pepper strips.

Slice the duck breasts across the grain into thin slices and arrange over the greens. Sprinkle with the chervil and optional truffle.