I would personally avoid leaving the bark on a charctuterie board simply because of the cleaning issues. I have done a number with "natural edge", where I peeled the bark off and gently rounded the pokey bits but still trying to preserve the "character" and those worked pretty well.
If you decide to go ahead.. cedar bark is pretty porous so personally I'd want to saturate it pretty well. I've had good luck with both cyanoacrylate and epoxy. The CA tends to work better on thinner strips of bark where you don't need as much penetration, I'd be slightly concerned in this case that you wouldn't get a great bond along join with it. It might still work pretty well though and has the advantage over epoxy of not building up much, that is the thin stuff soaks right in.
For the epoxy I'd heat the piece of wood up to 90-100F and then pour the resin onto it so that its pulled in as it cools. The trick there would be to avoid getting to thick of a resin coating on the actual outside of the bark, some judicious use of tape dams and not getting to close to the edge should work but I'd experiment with a scrap of the actual wood in use first. You might have to do a couple of coats. Shave epoxy back to the wood back after to get rid of any surface resin. This may also cause some "finishing" problems, but if you're just doing wax & mineral oil that will sit on top of epoxy as happily as it does on wood.
