If the Dutch passport holders want to apply visa at Vietnam Embassy, they should to know that:
Visa administrative Institution: Vietnam Embassy
Processing time: depends on you how fast you need. But for sure, you should make a call to Vietnam Embassy for details.
Required Documents: passport, money and 1 new envelope with stamp on it and your exact home address in order to avoid losing issues.
How to apply: please take a look at contact information of Vietnam Embassy below
EMBASSY OF VIETNAM IN THE HAGUE, NETHERLANDS
Address: Javastraat 1, 2585 AA The Hague, the NETHERLANDS
Phone: +31 (0)70 364 8917 | +31 (0)70 364 4300
Emergency number: +31 (0)6 330 532 86
Fax: +31 (0)70 364 8656