Mix the cucumber with the onion, castor sugar, salt and cider vinegar. Leave to marinate for about 1 hour. Cut the smoked salmon into 16 to 20 slices about 1/8- to 1/4-inch thick, cutting straight down onto the skin. Wrap one slice around your finger and set in the center of a large plate. Wrap 3 or 4 more slices around the center slice to form a rosette. Repeat the process to make 3 more rosettes. Drain the cucumber slices and arrange them in a circle around the smoked salmon rosettes. Garnish with sprigs of flat-leaf parsley, dill or chervil. Yield: 4 servings NOTES : Recipe Courtesy of Darina Allen of Ballymaloe Cookery School Recipe by: Cooking Live Show #CL8842 Posted to MC-Recipe Digest V1 #523 by Angele Freeman on Mar 19, 1997