Tortious interference is the deliberate interference with a contract between the target and a third party, and generally requires the intent to disrupt performance of that contract. Submitting fake job applications doesn't fit the bill: there's no contractual relationship that it interferes with.
I agree, I mistakenly thought the job portals were those of placement agencies and temp worker agencies. If the job portal is run by a subcontractor (job placement agency) then it could be tortious interference.
