Marinate the chicken: In a large bowl, whisk olive oil, garlic, spices, salt, pepper, lemon juice, and optional yogurt. Add chicken and coat well.
Cover and refrigerate at least 30 minutes, up to 12 hours for best flavor.
Cook your base: Prepare rice or quinoa according to package directions. Fluff and set aside. If using greens as your base, rinse and pat dry.
Make the yogurt sauce: Stir yogurt, garlic, lemon juice, and optional tahini or olive oil.
Season with salt. Thin with a splash of water until drizzleable. Chill until serving.
Cook the chicken (stovetop): Heat a large skillet over medium-high.
Add a light drizzle of oil. Cook chicken 4–6 minutes per side (thighs) or 3–5 minutes per side (breasts), until browned and cooked through. Rest 5 minutes, then slice.
Or cook the chicken (oven/broiler): Heat oven to 425°F (220°C).
Arrange chicken on a lined sheet pan. Roast 15–20 minutes, then broil 2–3 minutes for charred edges. Rest and slice.
Prep veggies: While chicken cooks, chop tomatoes, cucumber, red onion, and parsley.
Set out pickled onions, avocado, and lemon wedges.
Assemble the bowls: Add a scoop of rice or quinoa (or a bed of greens). Top with sliced chicken, veggies, and parsley. Spoon over yogurt sauce.
Finish with lemon, a pinch of sumac or paprika, and hot sauce if you like heat.
Adjust and serve: Taste and add a pinch of salt or a squeeze of lemon to brighten. Enjoy warm or at room temperature.