Hiring someone to work in a virtual job requires a lot of trust. You won't see the person every day and won't be able to supervise their work as closely as you could if they came into the office. You need to hire workers who will thrive in that kind of situation. Make sure you ask interview questions that will help you judge whether the candidate is a good fit for that kind of work.
Does the candidate have any experience in virtual work?
If they were previously successful in a virtual job, that's a positive sign that they'll be effective as a virtual worker for you. Ask what challenges they faced in their previous virtual role and how they overcame them. Also find out about their home work environment to make sure they have the tools needed to get the job done.
Does the candidate have the motivation to work on their own?
A virtual worker needs to be able to take the seed of an idea and run with it to completion. Ask about what motivates them to get a job done and for examples of projects they completed remotely. Find out how they expect to communicate with their manager and co-workers and what kind of recognition they want for a job well done.
Does the candidate have the discipline to work on their own?
Along with being able to motivate themselves, virtual workers need to discipline themselves to do the work. They need to track projects and deadlines. Ask them what they do to stay on top of schedules. Find out how they deal with issues that make meeting schedules challenging, such as technical problems—do they tackle solving them for themselves, or does their work stop until someone else resolves the problem?
Does the candidate have the ability to solve problems on their own?
How will the candidate solve problems without input from colleagues? When they need input from someone else, how do they get it?
Does the candidate have the technical skills for the job?
Last but definitely not least, don't forget about the technical skills needed to do the job. Because the worker won't be able to pick the technical brain of a colleague one cubicle over, it's even more important they are highly qualified in the technology.