Any action against China by Vietnam will be felt like the annoying buzz of a mosquito. The Viets have come to this forum in force since the oil rig arrived but have presented no realistic argument about how to proceed foward.
Restrict movement of Chinese to Vietnam? Big deal!
Vietnam will forever be in the shadow of China, you can whinge, cry, threaten and moan but in the end you are too small to hit back in any meaningful way.
Deal with China bilaterally and you lose.
Deal with China as ASEAN bloc and you will still lose ( if you can even agree on anything as a group).
Ask the world for help and you will lose (No sane country would jepardize relations with PRC to fight on your behalf)
Lose, lose, lose.