In a bowl, whisk olive oil, lemon juice, garlic, and spices. Add chicken and marinate for 30 minutes to 12 hours.
Grill or pan-sear chicken over medium-high heat for 5–6 minutes per side. Let rest, then slice.
Cook your grain base (rice, quinoa, or cauliflower rice).
Slice all toppings: tomatoes, cucumbers, onions, olives.
Assemble bowl: grain base, chicken, toppings, tzatziki.
Garnish with herbs, lemon wedges, and optional chili flakes.
