Preheat skillet over medium heat. Season chicken breasts with salt, pepper, and half the cumin. Cook 5-6 minutes per side or until fully cooked. Let rest, then dice into bite-sized pieces.
Meanwhile, sauté riced cauliflower in same skillet 3-4 minutes until tender. Add garlic, remaining cumin, and a pinch of salt. Let cool slightly.
In a large bowl, combine cooked cauliflower, diced chicken, cucumber, tomatoes, parsley, and mint. Whisk lemon juice, olive oil, salt, and pepper to make dressing. Pour over salad and toss to coat. Chill 15-30 minutes before serving.