01 - In a medium mixing bowl, combine shredded chicken, mayonnaise, Greek yogurt, Dijon mustard, celery, red onion, dill, lemon juice, salt, and pepper. Mix thoroughly until all ingredients are fully incorporated and the mixture is creamy and well-blended.
02 - Wash and thoroughly dry the cucumbers. Using a mandoline slicer or vegetable peeler, slice cucumbers lengthwise into long, thin ribbons. Aim for approximately 16 even, pliable slices that will roll easily without breaking.
03 - Place a cucumber ribbon flat on a clean work surface. Spread about 1 1/2 tablespoons of chicken salad mixture evenly along one end of the ribbon. Add a few julienned carrots on top if desired for extra crunch and color.
04 - Gently roll the cucumber ribbon starting from the filled end, tucking in the filling securely as you roll. Place each finished roll seam side down on a serving platter to maintain its shape.
05 - Repeat the rolling process with remaining cucumber ribbons and chicken salad until all ingredients are used. Arrange all roll ups on the platter, ensuring they sit stable with the seam facing downward.
06 - Serve immediately for optimal crispness, or cover the platter and refrigerate for up to 2 hours before serving. Note that extended refrigeration may cause cucumbers to release moisture and lose some texture.