In a mixing bowl, combine olive oil, minced garlic, lemon juice, salt, and pepper. Coat the chicken breasts generously and let them marinate for at least 30 minutes for maximum flavor.

Preheat your grill to medium-high heat, about 375°F. Cook the marinated chicken for approximately 6–7 minutes per side, or until it reaches an internal temperature of 165°F and is beautifully charred.

In a separate bowl, mix together Greek yogurt, grated cucumber (ensure it's squeezed to remove excess moisture), minced garlic, fresh dill, lemon juice, salt, and pepper until the mixture is creamy and well-combined.

In a saucepan, bring 2 cups of water to a boil. Add rinsed rice and a pinch of salt, then lower the heat and cover. Allow it to cook until fluffy, about 15 minutes, following the package instructions.

On a plate, create a base of fluffy rice, slice the grilled chicken on top, and drizzle with the creamy tzatziki sauce to finish.