saddle size?

ok so i bought my roomate a sun 20" uni for xmas… so that i could have someone to ride with… and i see that the saddle doesnt look to comfy nor does it have a handle so what seat could he get to put on there once he gets better and wants to venture off into hopping onto curbs and such?

http://www.einradladen.net/catalog/product_info.php?cPath=8&products_id=162&osCsid=1c7ba651526cca3eded2ba0209182f73

for the smaller pocket

and

http://www.einradladen.net/catalog/product_info.php?cPath=8&products_id=404&osCsid=1c7ba651526cca3eded2ba0209182f73

for the rich guy