Prepare the salad dressing
just before use. Add vinegar, apple
juice, Dijon mustard, salt, and pepper 1 at a time through the feed opening of a running blender
. Then, leaving the blender running, add the olive oil in a slow steady stream.
Cut the potatoes
into 1/4-inch thick slices and add to a mixing bowl. Slice the green beans
into 3/4 to 1-inch lengths and add to the potatoes. Fold in parsley and tuna
. Toss gently with enough dressing to coat and top with wedges of hard boiled egg.