To unlock all the characters in Table Tenis you dont need to go through tourniment mode, or even beat the tournments within time limits. An easier way to unlock the characters is to play the CPU a bunch of times. This can be done either in tournament mode or exhibition mode with any settings

Unlock Juergen 20 - wins
Unlock Kumi - 25 wins
Unlock Solayman - 30 wins
Unlock Carmen - 35 wins
Unlock Cassidy - 40 wins
Unlock Jung Soo - 45 wins
Unlock Mark - 50 wins