I couldn't say if this is authentic Mexican or not, but it's tasty, crisp and fresh. Basic idea came from a web site I was on about mexican cooking. Pull out your mandolin slicer or food processor to make quick work of the chopping.
Julienne the jicama, beets, and carrots. Mix together in a large bowl.
Drain the mandarin oranges, reserving liquid. Add the orange segments to the jicama mixture.
Remove the zest of 1 lime and set aside. Juice the limes, which should yield about 3 tablespoons Whisk up the lime juice and the zest with 1/4 cup of the mandarin orange liquid. While whisking, drizzle in the oil to make smooth vinaigrette. You could get away with a little less oil here if that's a concern. Check the flavour of the vinaigrette; if it's too sour for your tastes, add a little honey or agave nectar to take the lime edge off.
Pour the vinaigrette over jicama mixture. Add in the cilantro and toss to coat. Season to taste with salt and pepper.
Transfer the salad to a platter or serving bowl and sprinkle with the peanuts.