Cubed radish kimchi, or Kkadugi, can be found in any Korean market and Whole Foods or specialty grocer. Like standard Napa cabbage kimchi, Kkadugi is crunchy and it has a slight sweetness to it. Pairing it with slightly burned cabbage here provides a nice texture and flavor that plays well with the freshness of the cilantro, twang of the lime and the kick of heat from the jalapeno.