Try passing it directly to the ng-click function:
<div class="col-lg-1 text-center">
<span class="glyphicon glyphicon-trash" data="{{event.id}}"
ng-click="deleteEvent(event.id)"></span>
</div>
Then it should be available in your handler:
$scope.deleteEvent=function(idPassedFromNgClick){
console.log(idPassedFromNgClick);
}
Here's an example