EDIT: TL;DR: I see the primary problem with recruitment being far too many applicants for each job, because applicants apply to many, many jobs. Incentivise applying to only a few jobs and the employer gets fewer, better applicants.
For job-seekers, the marginal cost of one more application is too low, so companies get too many applications. With too many applicants, filtering becomes more random, so the reward for applying for a job you are only tenuously qualified for increases. It's a classic hawks vs doves with a big payoff for being a hawk amongst mostly doves
So, make it more expensive to apply for a job. Two ways I can think of doing this:
1. Charge applicants ten bucks to apply for a job. Have companies report if they were good enough but they found someone better. In that case, give them a refund. In all other cases, keep the money. (EDIT: This may possibly be illegal in some jurisdictions, but there are doubtless ways around that.)
2. Show companies how many jobs the applicant has applied for recently (not necessarily where they have applied, but you could perhaps positions/business areas) and/or restrict applicants to N applications per month. Aggressively detect and ban sock-puppetting — perhaps you can require verified ID of the applicant's name and get companies to check that is the name of the person applying.
You could also make things less stressful by operating on a say weekly or monthly cycle. Jobs are posted at the beginning of the month, applicants choose which N jobs they want to apply for, applications go out, new cycle starts. This avoids stampedes and requires applicants to be discerning.