Use a grater to shred 2 cups of jicama into a large bowl. Add cole slaw and Mandarin orange segments; set aside.
In a small bowl, whisk together reserved Mandarin juice, mayonnaise, vinegar, fajita seasoning, salt, and pepper.
Pour dressing over jicama mixture. Toss to mix thoroughly. Top with cilantro.
Recipe courtesy of Sandra Lee, 2008