Make the Greek dressing: Add the olive oil, red wine vinegar, Dijon mustard, dried onion, honey or sugar, salt, garlic, oregano, and black pepper to a jar with a tight-fitting lid.
Shake well: Secure the lid and shake vigorously until the dressing is thoroughly combined.
Marinate the chicken: Place the chicken breasts in a suitable dish or container and coat with some of the Greek dressing. Let the chicken marinate before cooking.
Cook the chicken: Cook the marinated chicken until golden on the outside and fully cooked in the center. Let it rest briefly, then slice into strips.
Prepare the vegetables: Combine the chopped cucumber, red onion, tomatoes, and Kalamata olives.
Cook the cauliflower rice: Heat a little olive oil in a skillet. Add the frozen cauliflower rice and season with garlic salt, pepper, and oregano. Cook until tender and heated through.
Build the bowl: Add cauliflower rice to each bowl and top with sliced chicken, vegetables, feta, tzatziki, and fresh dill or parsley.
Finish and serve: Drizzle with additional Greek dressing and serve with fresh lemon wedges.