Place the tortilla on a baking sheet coated with nonstick cooking spray. Bake for 3 minutes, or until golden brown. Remove from the oven and reduce the temperature to 350F. Spread the sour cream evenly over the tortillas. top with the spinach and tomato. Next, sprinkle evenly with the Monterey Jack cheese. Bake for 5 minutes more, or until the cheese is melted. Sprinkle with the green onions. Cut each tortilla into 6 slices and serve immediately.