Mix the marinade: In a bowl, whisk olive oil, lemon juice, red wine vinegar, garlic, oregano, cumin (if using), salt, pepper, and paprika until combined.
Marinate the chicken: Add chicken to the marinade, toss to coat, and let sit for at least 20–30 minutes. For best flavor, marinate up to 4 hours in the fridge.
Cook your base: Prepare rice, quinoa, or couscous according to package directions.
Fluff and keep warm, or chill if serving as a cold bowl over greens.
Make the tzatziki: Stir together Greek yogurt, grated cucumber, lemon juice, olive oil, garlic, dill, salt, and pepper. Taste and adjust lemon or salt. Chill until ready to serve.
Prep the veggies: Chop tomatoes, cucumber, and greens; slice red onion.
Pat veggies dry so the bowl doesn’t get watery.
Cook the chicken: Heat a large skillet over medium-high. Add a light drizzle of olive oil. Sear chicken in a single layer for 4–5 minutes per side, until browned and cooked through (165°F/74°C).
Work in batches if needed for good color.
Rest and slice: Transfer chicken to a plate and rest 3 minutes. Slice or leave in chunks. Squeeze a little lemon over the top for brightness.
Assemble the bowls: Add your base, then layer chicken, tomatoes, cucumber, onion, and greens.
Top with olives, feta, herbs, and a generous spoon of tzatziki.
Finish: Add a squeeze of lemon and a light drizzle of olive oil. Taste and adjust salt and pepper.