Witnesses said that the black-clad, balaclava-wearing assassins approached Kavanagh at 5.25pm on the terrace of Harmon's Irish Bar in the Elviria shopping centre and opened fire, just 500 metres from the luxury Don Carlos hotel where a Spain-USA forum was taking place.
Spain's defence minister had spoken there earlier in the day and the US ambassador to Spain was also in attendance at the high-security event.
According to local daily Sur, witnesses said the men "looked like ninjas".
The first shot hit Kavanagh in the arm then he received further bullets to the back as he attempted to flee inside to safety. The final shot was to his head.
A car parked nearby was hit by a stray bullet but no bystanders were hurt.
The killers escaped on foot but a black BMW was found burning some five KM away in the direction of Marbella.
The Irish Sunday Independent newspaper reported that Kavanagh, who was nicknamed 'Hatchet', was a convicted heroin dealer known to Irish police as a violent gang enforcer who collected debts.
He was said to have lived in Spain for some years but to have returned to Dublin earlier this year in an unsuccessful attempt to recover money owed to a Spanish cartel by an Irish drugs gang .
Police took a number of statements and DNA samples at the crime scene and investigations are ongoing.