The Minnesota Bonsai Society has a great article on how to make Chopsticks out of bamboo. This style of chopstick is much better for potting and re-potting Bonsai trees. The end of the chopstick is angled up to push the soil upwards when potting/re-potting trees. This is really helpful when trying eliminate air pockets in the soil. You can buy larger bamboo from garden centers and split the bamboo into smaller pieces etc.
Ryan Neil from Bonsai Mirai recommends using the same style of chopsticks.
Hint: Expand the window when looking at the photos and you can really see what they are talking about in the article.
Photo courtesy of Minnesota Bonsai Society.