Hello Soudick!!
I work at MJV as duty Manager for Iberia Handling and can give you some info on Murcia but no that much on Alicante.
The main handling agents at Murcia Airport are Iberia Handling (the one I work for) and Swissport Menzies.
Swissport is currently offering some vacancies for ramp agents due to the increase in traffic during the summer season. The basic contract is a part time one (about 20/25 hours a week) and of course not a fixed one to start with.
Iberia will soon start recruiting ramp agents and if you are picked out after going through several tests, they offer you a 6 hour contract that changes everyweek depending on the activity we have raising up to 36 a week.
According to the experience I have, none has ever worked less that 25 hours per week even the contract is based on 6
I hope the info can be of help
best regards