Simply put give the applicant an NDA and hire him/her as a consultant. Assign her/him a task that creates value for your company, do not go with a pet or PoC project, that is just waste you should eliminate in your lean process.
You need VDI for this. You want an isolated Desktop with access to few resources, no clipboard availability and proxy controlled access to the web. You want to make sure the person you are hiring will not go evil.
Pay the Applicant (now the Consultant) for her/his work and if you like the outcome (which goes beyond human relations, commitment, availability, hard work, knowledge ...) then approve her/him. When the new member joins the team there is already confidence in all parts involved, there are no surprises.
IT personnel are knowledge workers. You should have a layered infrastructure, architecture and SDLC in place respecting Separation Of Concerns. If you do so, then you should be able to define tasks that demand little or no knowledge of the current services you provide or the nature of your business. That translates into new team members that are less stressed, who provide value day one and who only keep providing more and more gradually as they learn.
While the technical manager discusses the intrinsics of the first few tickets that will help with your project there will be a full understanding of the capabilities of the applicant. The applicant himself will understand if this job is the right one, if the technology stack makes sense to her/him, if s(he) sees potential for growth. It is a win-win situation.
We should all learn from the Automobile Industry. It is easy to build a Software Shop. It is not that easy to build a Software Factory.
Let us practice an agile approach to hiring. Lean processes start at hiring and they go all the way up to to Strategic Planning. Agility in SDLC is not enough to make a business succeed.