Preheat oven to 350°F Place ten 3.5-inch tart pans on top of a baking sheet and spray with nonstick spray.
Add the cauliflower rice to a food processor and pulse until finely ground. Cook the cauliflower in the microwave, according to package instructions. Let cool. Squeeze out as much liquid as possible from the cauliflower, using a dish towel to wring out the moisture.
Transfer the cauliflower to a bowl and add the remaining crust ingredients. Mix together with a fork.
Add about 2 tablespoons of the mixture to each of the tart pans and press evenly into the bottom and up the sides.
Bake 15-20 minutes, or until golden brown. Let cool.
Remove the cauliflower pie crust from the tart pans. First remove the outer ring. Then carefully use a small offset to separate the bottom of the crust from the bottom of the tart pan. Place pie crusts on a parchment-lined baking sheet.
For the Pizza Filling:
Heat about 1 tablespoon of olive oil in a small skillet over medium high heat. Add the sausage and cook until browned, about 7-10 minutes, breaking up with a wooden spoon. Drain on a paper towel lined plate.
Add 2 teaspoons of tomato sauce to each crust and spread. Top with mozzarella, sausage crumbles, onions, peppers and olives.
Bake 7-10 minutes, or until cheese is melted and bubbly.
Combine the remaining tomato sauce, sausage, onions, peppers and olives in a bowl and microwave until warm. Serve on the side with the cauliflower pizza pies.