This is a very simple project that's versatile, cheap, and produces authentic results.
Step 1: Cutting
The trick is to cut the wood slice when the wood is cold and somewhat dry. I used a chainsaw, because power tools are awesome, and who doesn't want to use a chainsaw? But really any saw works - just be sure to slice straight so you don't end up with a trapezoidal type shape. String or calk markings help.
Once cut, bring the piece inside! I left mine to sit out overnight and returned to a nice big split.
Step 2: Sanding
If you are new to sanding, start with a coarse grain and incrementally move to fine grain. I went from 80 grit, to 120 grit, and finally to 220 grit. The image shows a sanded disk (left) and non-sanded disk (right).
Technically, you only need to sand one side, but I don't believe in half-ass measures.
Step 3: Oiling and Underpadding
If you are going to use the slice as a cutting block, or for direct food contact, use a food safe oil! Most hardware or wood shop stores have their own mixes/versions. You do not have to spend a lot of money, and can certainly make your own concoction. I simply spread it out with my fingers, and re-applied as necessary.
Oiling is very important, as any liquid will otherwise stain the wood. Not oiling also leaves the wood susceptible to water damage. Furthermore, be sure to oil BOTH sides in turn, and let them dry freely.
As a final touch, I have a loose piece of non-slip under-padding cut out. That's it!