Whisk together olive oil, lemon juice, garlic, oregano, cumin, paprika, salt, and pepper to make the marinade.
Coat chicken thighs in the marinade. Cover and refrigerate for 30 minutes.
Grate cucumber and squeeze out excess moisture using a clean kitchen towel.
Mix Greek yogurt, grated cucumber, garlic, lemon juice, dill, and salt to make tzatziki. Chill until ready to use.
Cook marinated chicken on a skillet or grill pan over medium heat until cooked through (internal temp: 165°F).
Slice the cooked chicken thighs into strips.
Prepare basmati rice according to package instructions (or use rice cooker).
Assemble bowls with rice, chicken, cherry tomatoes, diced cucumber, red onion, olives, and feta.
Top with tzatziki sauce and fresh parsley. Serve immediately.