Prepare the Cucumber Ribbons: Wash and dry the cucumbers. Using a mandoline or a wide vegetable peeler, slice the cucumbers lengthways into long, thin ribbons, about 1.5mm thick. Stop when you reach the seedy core. You should get about 10-12 usable ribbons per cucumber.

Dry the Ribbons: Lay the cucumber ribbons on a tray lined with paper towels in a single layer. Place another paper towel on top and gently press down to absorb as much excess moisture as possible. This is the secret to a neat roll up! Let them sit while you prepare the filling.

Make the Dressing: In a large mixing bowl, whisk together the mayonnaise, Greek yoghurt, Dijon mustard, chopped dill, parsley, and lemon juice until smooth and well combined.

Combine the Chicken Salad: Add the shredded or diced cooked chicken to the bowl with the dressing. If you're using it, add the finely diced celery now. Stir everything together until the chicken is evenly coated.

Season to Taste: Season the chicken salad with salt and black pepper. Give it a final stir and taste it, adjusting the seasoning if necessary. You might want a little more lemon juice for brightness or a touch more salt.

Assemble the Roll Ups: Lay two or three cucumber ribbons on a clean work surface, overlapping them slightly to create a wider "wrap" about 8-10cm wide. What works best for me is a three-ribbon width.

Fill and Roll: Spoon about 1-2 tablespoons of the chicken salad mixture in a line at one end of the overlapped cucumber ribbons. Gently but firmly, roll the cucumber up and over the filling to create a neat, compact cylinder.

Serve: Place the finished cucumber roll ups seam-side down on a serving platter. You can secure them with a cocktail stick if you like. Serve immediately or chill for up to an hour before serving.