The simulator vendors offer training. We use Laerdal and they have a 1-2 day class on each type of mannequin that you can purchase for a group of staff. METI also has similar training.
The NLN has some online learning modules shown on the home page that can be used. They cover things like realism and debriefing. These might be helpful depending on how your tech will be working.
Techs work in so many different ways that are unique to each center. So, I am not aware of any official certification. We use the above and then conduct on the job training.