1. Place the cauliflower into a food processor and pulse until it resembles traditional rice, like a coarse meal.
2. Place into a large bowl, scraping down the sides with a spatula.
3. Add the tomatoes, parsley, cilantro, celery, and green onions into the bowl. In a separate bowl stir together the ingredients for the dressing and then pour onto the cauliflower mixture. Toss well to combine. Adjust salt and pepper to taste. Refrigerate for 30 minutes before serving.