This is one of my favorite Paleo friendly techniques. It is an interesting use of an often overlooked piece of produce.
You will need:
Oxo mandolin http://amzn.to/1oU8X8I
Cut both the top and bottom off your jicama.
Begin to peel the skin with the knife and your fingers if the the skin gives easily. Don't try a vegetable peeler unless you have all day. You may lose a tiny amount of jicama to the compost by starting your strips with the knife, but the worms will thank you.
After you have the jicama completely peeled lay it on your mandolin. You want to eyeball it to trim the edges off so it will plane perfectly down the channel.
This is very important!
If the jicama is too wide it will cause pressure leading to uneven tortillas. If you cut it too narrow you will have tiny tortillas.
Score the jicama where you want to cut it first. Then trim the edges with the knife and the plane the edges with the mandolin itself. Check the width every cut or two to be sure of what you are doing .
Once you have the edges squared to the side you are ready to slice the bottom of the jicama. You can flatten the bottom with the knife first or just begin slicing. It will take a few passes before the pieces are large enough for tortillas. You can save these edges and trimmings for a salad or slaw.
Watch your fingers and go to town. It's best to check the side dial every few cuts to be sure you are at the thickness you want and to keep checking that the sides are square in the channel and not binding.
Once I have a stack of tortillas I like to trim the edges to make them more uniform. You can then store covered in water in the refrigerator. To use them take them out of the water and onto a heated pan or griddle. The steam with keep them pliable and the skin will begin to dry. You really can't undercook them as jicama is great raw. They will shrink if you leave them too long though so keep an eye on them unless you want chips!
Fill with your favorite meat/fat/veg and enjoy!
To make them rocket tacos:
Simmer your favorite meat (I used fatty ground pork) with some cumin, red pepper, and sea salt.
Fill the shells and add a guacamole made in a blender cup with
half a bunch of cilantro
Juice of 2 limes
Add fresh chopped fresh arugula (or your favorite green)