Lay a tortilla flat on your cutting board. In a small bowl, stir together the softened cream cheese, garlic powder if using, and salt until smooth. Trying to spread cold cream cheese tears the tortilla, so give it at least 20 minutes at room temperature first.

Spread half of the cream cheese mixture across the tortilla in an even layer, going almost to the edges but stopping about half an inch from one long side. That bare strip helps seal the roll at the end.

Scatter half the shredded carrots, diced cucumber, and chopped spinach evenly over the cream cheese. Press the vegetables gently toward the center of the tortilla with your fingertips so they do not all shift to the ends when you roll.

Starting from the side that has filling all the way to the edge, roll the tortilla away from you as tightly as you can without tearing it. Give it a gentle squeeze along the length once it is rolled to firm it up. Wrap it snugly in plastic wrap and twist the ends closed.

Refrigerate the wrapped roll for at least 15 minutes. This rest period firms the cream cheese so the pinwheels hold their round shape when sliced. Repeat with the second tortilla.

Unwrap and place the roll on your cutting board. Using a serrated knife, slice into rounds about 1 inch thick using a gentle sawing motion. A serrated blade grips the tortilla instead of squishing it flat. Each roll yields about 6 pinwheels. Arrange on a plate or pack directly into a container.