Preheat the oven to 350°F.
Unroll the crescent rolls onto a nonstick baking sheet, separating the dough and arranging it in a single layer covering the entire baking sheet. Press together the perforations, and then using a fork, prick the dough all over. Bake the dough for 10 minutes until golden brown then remove it from the oven and allow it to cool completely.
In a medium bowl, combine the cream cheese, mayonnaise and Ranch dressing mix. Using a handheld mixer, blend together the ingredients until smooth and creamy. (Alternately, beat the ingredients together in a stand mixer fitted with the paddle attachment.)
Spread the cream cheese mixture onto the completely cooled baking sheet of crescent rolls, covering the entire surface in an even layer.
Sprinkle the grated broccoli, cauliflower, carrots, tomatoes and scallions on top of the cream cheese then place a piece of parchment paper or wax paper on top and lightly press down the veggies. Cover the baking sheet securely with plastic wrap and refrigerate the bars for a minimum of one hour and up to overnight.
When ready to serve, slice the sheet into bars and serve.