Gluing up thin strips of multiple types of wood to create a larger multi-colored board that I call "Rainbow Wood" is easy to do if you've got the proper woodworking tools and allows you to have some pretty cool stock material on hand for projects that could use it.
Follow the steps in this Rainbow Wood Instructable
and make up some stock material.
You can also skip this step and use any kind of hard wood that you like.
Take your stock material and slice a piece off in the table saw using a crosscut sled. The width of your cut will equal the width of your chopstick rest. I cut off around 1 1/8".
The thickness of the rest is determined by the thickness of the stock. The length of the rest will be determined by another cut that comes later.