Preheat oven to 400°F. Line a cookie sheet with parchment paper or a silpat baking mat.
Unwrap puff pastry sheet and cut into 9 squares. Stretch each square out just a little bit.
Stir together pumpkin, sugar, and pumpkin pie spice. Place about 1/2 tablespoon of filling in the center of each puff pastry square. Sprinkle about 1 teaspoon of white chocolate chips on top of the pumpkin mixture. Roll the two sides up over the top, overlapping them. Pinch the ends with a fork to seal.
Place croissants evenly on cookie sheet and bake for about 13-15 minutes. Cool before glazing.
To make the glaze: melt 1/4 cup white chocolate chips with oil in a small bowl on 50% power in the microwave. Heat in 30 second increments, stirring between each, for about 1 minute total (depending on your microwave). Stir in cinnamon. Drizzle over croissants. (I placed my glaze in a ziploc sandwich bag and cut off one tip to drizzle.) Let set then serve. Best eaten the same day they are made.