In small bowl, combine all dressing ingredients; blend well. Set aside.
Hollow out and discard center of each cucumber section, leaving about 1/4 inch around outside. Place 1 cucumber section, cut side down, on each salad plate.
On work surface, layer 1 or 2 lettuce leaves, 1 piece endive and about 1/8 of the mushrooms. Roll and gather lettuce at bottom to enclose endive and mushrooms. Tuck rolled lettuce into 1 cucumber section. Repeat with remaining lettuce, endive, mushrooms and cucumber sections. Garnish with edible flowers. Serve with dressing.