Q:

How to ask rejected full-time candidates to apply to teach individual courses?

My department has a number of courses we need covered by adjuncts in the next academic year. We were given permission to hire one (and only one) salaried adjunct and to cover the rest of the courses with per-course adjuncts. Salaried adjuncts receive benefits and are better paid than per-course adjuncts.
We received excellent candidates for the salaried position, only one of whom we can hire. After we close the search, (how) can I approach rejected candidates about teaching individual courses at the lower rate? Some career adjuncts have told me it would be offensive to offer a lower-paying and lower-status position to someone who applied for a better one, and I do not wish to offend anyone. 
While the salaried position was publicly advertised, our institution does not advertise single courses. Furthermore, most of the candidates who applied for our salaried position were invited to by committee members or by our contacts, not because they were looking at ads.
How can I get the best outcome for our students and for teachers who would be willing to teach individual courses? I will continue to ask the administration for permission to hire a second salaried adjunct but do not expect to receive it. There is not much time to wait before starting our per-course search, as the current academic year is nearing its end (and our administration moves very slowly).
Update
Because each of the top two candidates seemed too good to reject, we proposed a second salaried position, which we made by cobbling together the remaining courses and one from a related program. To our surprise, the administration reversed its earlier decision to let us hire only one salaried adjunct, and we were able to make two salaried offers. While my question is moot, I will leave it up for future search chairs.

A:

Don't ask them. It's a smack in the face. Advertise the position in the same place you advertised the salaried one; they will see it if they are still looking, and apply if they feel they need to.

A:

Ask them. What other option do you have? Not asking them I guess, but then you're making the decision for them. Personally, I can't imagine being offended if you explain it the way you did above. That said, I do agree that most candidates will react the same way other answerers have ("no freaking way!") -- all the more so because they were personally recruited for a permanent, salaried position.  
You should have a firm offer for a specific course rather than just "inviting them to apply" for the lesser position. If possible, personalized mails or phone calls tend to be better received than form letters. 
Edit: a lot of this discussion has focused on whether offering the lesser position is offensive. I think it's not, but beyond that, the question was:

How do I get the best outcome for our students and for teachers who would be willing to teach individual courses.

Even if applicants are offended by being offered the lesser position, that has zero bearing on the students or teachers that OP is asking about. Frankly, it doesn't really matter whether the rejected applicants are offended -- this will have no real consequences. On the other hand, if even one of these applicants accepts the per-course position, that could have huge consequences for both the students and teachers in question.

A:

This sucks, but it is the reality of the academic job market. Basically, you want to offer them (hopefully), or ask them to apply (less nice, bordering on rude), the same job but now you are going to pay them less, likely substantially less, with fewer benefits and no long term security. Now, here is the hard part. If you don't offer them the worse job, they are going to walk away thinking they were not even good enough to adjunct on a per-course basis. I think that is worse than being up front.
You just need to be up front. Say "We cannot offer you the position you applied for." Then tell them you have a much less desirable position that they are clearly overqualified for, but if they are interested you would be happy for them to apply. If you actually want them to take the job, you also need to demonstrate that your department respects per-course adjuncts, despite the university clearly not respecting them. That is the hardest part. You cannot mislead them and pretend that there is a carrot (i.e., the job they applied for and the one you are trying to get them). It sounds like you care, but hopefully you have some evidence of why they should expect to be treated fairly.

