Kangkong is a very popular in vegetable in Singapore! It holds relations to the Convolvulaceae family of greens, that is also related to sweet potatoes. It however, does not resemble traditional Spinach.
 
Commonly found at ZiChar stalls, its a vegetable that is prefably cooked with Sambal (A traditional Chili paste in Singapore).
 
Kangkong has very little calories - just about 48 calories per 250 grams. It is crunchy and carries a mild taste for greens of similiar. Kang kong leaves contain excellent levels of ascorbic avids and vitamin-C. Just 100 grams of Kang kong  could provide 55 miligrams or 92% of daily required values of Vitamin C. It is also an abundant source of vitamin-A, smiliar to those of watercress and kale. 
 
Preperation for kangkong is easy. Throw them into a wok just after sauteeding some garlic, onions and Sambal paste.