Boil salted water in a medium saucepan and cook the haricot verts until crisp-tender, about 3 minutes. Drain and rinse under cold running water until cool. Cut the haricot verts into 1/2-inch lengths.
In a large bowl, combine the romaine hearts with the cooked haricot verts, watercress, frisee, arugula, apple, pear, avocado and cheese. Toss with the dressing, season with salt and pepper and serve at once. Serves 4.
*Idiazabal cheese is a smoked, pressed sheep cheese from the Basque region. Manchego makes a fine substitute.