01 - Combine shredded chicken, mayonnaise, Greek yogurt, Dijon mustard, celery, red onion, dill, lemon juice, salt, and pepper in a medium mixing bowl. Mix thoroughly until all ingredients are evenly distributed and the mixture is creamy and well blended.
02 - Wash and dry cucumbers thoroughly. Using a mandoline slicer or vegetable peeler, slice cucumbers lengthwise into long, thin ribbons. Create approximately 16 even slices for consistent rolling.
03 - Lay a cucumber ribbon flat on a clean work surface. Spread about 1 1/2 tablespoons of chicken salad mixture along one end of the ribbon. Add a few julienned carrots on top if using for extra crunch and color.
04 - Gently roll the cucumber ribbon from the filled end, tucking in the filling as you roll to secure it inside. Place each roll seam side down on a serving platter.
05 - Continue the process with remaining cucumber ribbons and chicken salad until all filling is used, creating approximately 16 roll ups.
06 - Serve immediately for optimal crispness, or cover and refrigerate for up to 2 hours before serving. For best texture, avoid refrigerating longer than 2 hours as cucumbers may become watery.