Marinate the chicken: In a bowl, whisk olive oil, lemon zest and juice, garlic, oregano, cumin, salt, pepper, and red pepper flakes. Add chicken and toss to coat.
Cover and refrigerate for at least 30 minutes, ideally 2–4 hours for deeper flavor.
Cook your base: Prepare rice or quinoa according to package directions. Fluff with a fork, then stir in olive oil and a pinch of salt. Let it cool slightly so it doesn’t steam up the containers.
Mix the tzatziki: Combine yogurt, grated cucumber (very important to squeeze out moisture), olive oil, lemon juice, garlic, dill, salt, and pepper.
Taste and adjust lemon or salt. Chill until ready to pack.
Prep the veggies: Dice cucumber and bell pepper, halve tomatoes and olives, slice red onion thinly, and chop the herbs. Keep them dry—pat with paper towels if needed—so they stay crisp in the fridge.
Cook the chicken: Skillet/Grill Pan: Heat a drizzle of oil over medium-high.
Cook chicken 5–7 minutes per side (thighs) or 4–6 minutes per side (breasts), until browned and cooked through. Rest 5 minutes.
Oven: Arrange on a sheet pan and bake at 425°F (220°C) for 15–20 minutes, or until internal temperature reaches 165°F (74°C). Broil 1–2 minutes for char if desired.
Slice and season: Slice or cube the rested chicken.
Squeeze a little fresh lemon over the top and sprinkle with chopped dill or parsley for extra brightness.
Assemble the bowls: Divide the rice or quinoa evenly among containers. Top with chicken, then add sections of cucumber, tomatoes, red onion, olives, and bell pepper. Sprinkle with feta and herbs.
Add the sauce smartly: Portion tzatziki into small lidded sauce cups, or keep in a separate jar to prevent the grains from getting soggy.
Cool and store: Let bowls reach room temperature (no more than 30 minutes).
Seal and refrigerate. Add lemon wedges to each container if you like a fresh squeeze at mealtime.