Jicama is a wonderful vegetable. It is available year-round, delicious raw or cooked, low in calories, high in potassium, and keeps, uncut, in the refrigerator for up to three weeks.
Place the jicama in a mixing bowl. In a small bowl, whisk together 1 teaspoon of the jalapeno, the juices, vinegar, cilantro, and salt. Pour over the jicama, toss gently, and season with salt and pepper.
Arrange the slaw on 4 salad plates, garnish with the remaining jalapeno, and serve.