In a bowl, combine olive oil, minced garlic, lemon zest and juice, oregano, salt, and pepper.
Place chicken breasts in the mixture, ensuring they are well coated. Marinate for at least 30 minutes, or overnight for more flavor.
Preheat your grill to medium-high heat.
Grill chicken for about 7-10 minutes per side, until the internal temperature reaches 165°F (74°C) and juices run clear.
Allow chicken to rest for 5 minutes before slicing.
Combine Greek yogurt, grated cucumber, minced garlic, chopped dill, and lemon juice in a bowl.
Season with salt and pepper to taste. Chill in the refrigerator until ready to serve.
Mix together chopped pistachios, parsley, lemon zest, minced garlic, and olive oil in a bowl.
Season with salt to taste. Set aside for serving.