I personally managed to make a kind of dirty hack for iOS. If you choose to implement this workaround, you will lose the current date selected circle. The basic idea is on every selection (in the SelectionChanged event), I move the current date to some date far away from the past, in my case: 01.01.2000 - this date should be some date that you are sure the users will not click on. This causes the SelectionChanged event to be invoked again, but I stop it with a check from a boolean flag. Here is a sample implementation:
var calendar = (RadCalendar)sender;
dateChangedFlag = true;
calendar.SelectedDate = new DateTime(2000, 1, 1);
dateChangedFlag = false;
It is not perfect, but it does the job.
Hope this helps,