Start by finely grating one medium cucumber. Wrap it in a paper towel and squeeze out excess moisture. Set aside.

In a medium bowl, combine one cup of Greek yogurt, prepared cucumber, two tablespoons of dill, juice of one lemon, and one clove of garlic. Season with salt and pepper to taste. Mix well.

Shred two cups of cooked rotisserie chicken into bite-sized pieces and add it to the tzatziki mixture.

Finely dice half a red onion and add it to the bowl. Gently fold into the mixture.

Toss all the ingredients together until evenly coated with tzatziki sauce.

Serve immediately or transfer to an airtight container and refrigerate for up to three days.