Make the marinade: In a bowl, whisk the olive oil, lemon juice, red wine vinegar, garlic, oregano, cumin, smoked paprika, salt, and pepper until emulsified.
Marinate the chicken: Add chicken to the marinade and toss to coat. Cover and chill for at least 30 minutes (up to 8 hours). Longer marinating means deeper flavor.
Prep the tzatziki: Mix Greek yogurt, grated cucumber (squeeze out as much water as possible), lemon juice, olive oil, garlic, dill, salt, and pepper.
Chill to let flavors meld.
Rice the cauliflower: Pulse cauliflower florets in a food processor until rice-like. Or use pre-riced cauliflower to save time.
Cook the cauliflower: Heat 1 tablespoon olive oil in a large skillet over medium heat. Add cauliflower rice, season with salt and pepper, and cook 5–7 minutes until tender but not mushy.
Set aside.
Cook the chicken: Heat a grill pan or skillet over medium-high. Cook chicken 5–7 minutes per side (thighs may need longer) until the internal temperature reaches 165°F (74°C). Rest 5 minutes, then slice.
Prep the toppings: Halve tomatoes, dice cucumber, slice red onion, halve olives, and crumble feta.
Chop fresh herbs.
Assemble the bowls: Start with a bed of cauliflower rice. Add sliced chicken, tomatoes, cucumbers, red onion, and olives. Dollop with tzatziki and sprinkle with feta and herbs.
Finish and serve: Drizzle with a little olive oil and an extra squeeze of lemon.
Season to taste. Enjoy warm or at room temperature.