Preheat oven to 425 degrees.
Heat the olive oil in a medium skillet over medium heat. When the oil shimmers, add the mushrooms and season with salt and pepper.
Sauté for 8-10 minutes or until mushrooms are softened. Drain on paper towels.
Line a large baking sheet with aluminum foil.
Divide pizza sauce between the flour tortillas and top with precooked sausage, cooked mushrooms, and top with mozzarella.
Sprinkle with oregano.
Bake for 5-7 minutes, or until tortillas are crispy and the cheese is browned and melted.