In a mixing bowl, combine olive oil, lemon juice, minced garlic, dried oregano, ground cumin, paprika, salt, and pepper. Add chicken breasts, cover, and refrigerate for at least 1 hour.

Preheat grill to medium-high heat (about 400°F/200°C). Grill chicken for 6-7 minutes per side until internal temperature reaches 165°F (75°C). Let rest for 5-10 minutes before slicing.

In a medium bowl, mix together Greek yogurt, diced cucumber, chopped dill, chopped mint, and a pinch of salt. Stir until well combined, then refrigerate.

In serving bowls, layer a base of brown rice or quinoa. Add cherry tomatoes, red onion, Kalamata olives, and feta cheese. Place sliced grilled chicken on top.

Drizzle cucumber yogurt sauce over each bowl and sprinkle some red wine vinegar. Optionally, drizzle remaining olive oil.

Garnish with fresh parsley. Serve immediately, optionally with warmed pita bread on the side.