Just to get it out of the way, first off, jicamas look unappetizing. Like you'd imagine an ent's testicle would resemble. Or, less graphically, a warty, old potato. Nevertheless, I was excited to see them, as I knew they were grist for my blogging mill, so to speak.
As the name probably suggests, jicamas are native to Mexico. Alternate titles for it are yam bean, Mexican potato, and Chinese potato (the last one because the Spanish took jicamas to the Philippines hundreds of years ago, and from there they spread throughout parts of Southeast Asia). Botanically they're a legume. The plant itself is almost comically dangerous--every part of it save the root is poisonous, and even the skin of the root is toxic, too. They tend to be a roundish or oval shape, and about the size of a large orange or a grapefruit.
They're a fairly versatile food. Jicamas are often eaten raw, with salt, chili powder, and lemon juice. Some folks put them in salads. Other methods are slicing them and frying them into chips, adding them to soups, or stir frying them.
Given my extreme aversion to cooking, or even doing much food preparation, it should surprise no one that I chose to eat mine raw. Alas, due to moving around for the holidays and work, I didn't have any chili powder or lemon juice available. So I tried some pieces plain, some with mustard on them, and some others with a salt coating. The results were pretty unimpressive. As I'd read, I found the texture, and flavor, to be similar to a bland apple. The mustard, and especially the salt definitely helped, but even with these the jicama was mediocre at best. I would consider having them again, but I think only if it was cooked up in a restaurant dish.
But, to give them credit, these root vegetables are healthy to eat. They're low in calories, as well as in fat and sodium. Plus they have decent amounts of fiber, potassium, and Vitamin C.
The source for my jicama was Frieda's of California, although it was grown in Mexico. Frieda's tagline was ,"Inspire. Taste. Love." Which is much more dramatic and positive than my experience with them was.