Strain the Greek yogurt in a fine-mesh sieve lined with cheesecloth or a coffee filter for at least 2-3 hours (or overnight in the refrigerator) to remove excess liquid. This step is crucial for a thick and creamy dip.

Peel, seed, and finely grate the cucumber. Place the grated cucumber in a sieve, sprinkle with a pinch of salt, and let it sit for about 10 minutes to draw out moisture. Then, gently squeeze out as much liquid as possible using your hands or the back of a spoon.

In a medium bowl, combine the strained yogurt, squeezed cucumber, minced garlic, lemon juice, chopped fresh dill, and chopped fresh chives.

Season with salt and freshly ground black pepper to taste. Stir well to combine all ingredients.

For best flavor, cover the bowl and refrigerate for at least 1 hour to allow the flavors to meld before serving. This dip can be made ahead of time.