Yes, this can be challenging depending on where you are based. US, UK and Australian dietitians tend to be very well-trained, they have a 5-year masters degree and they need to be licensed/registered in order to practice.
If you don't live in any of those countries and don't trust your local dietitians, you can still look around the internet, many professional dietitians offer online counseling (via Skype and the like), which could be a perfectly valid alternative for you.
Regarding veganism, any dietitian under 40 years of age has received training on managing vegetarianism/veganism. That's an extremely common client profile so you really should not worry about that. It would be more difficult to find a dietitian who is also a buddhist meditator, but I honestly don't see how meditating can have a significant impact on your nutritional needs: it simply means you are probably less active than most people, and in any case, nutritional needs are estimated based (among other things) on your level of physical activity, and that would take into account the fact that you may be spending several hours sitting every day.