hyperLink.Attributes.Add("onclick", "javascript:void(viewer.show(" + picNumberlink + "))");

<a id="piclink_1" class="picLinks">...</a>
<a id="picLink_2" class="picLinks">...</a>

$('a.picLinks').click(function() {
    //split at the '_' and take the second offset
    var picNumber = $(this).attr('id').split('_')[1];
    viewer.show(picNumber);
});

var functionIWantToCall = function(){
    var wrappedLink = $(this);
    //some serious action
}

//this should be called on document ready
$("#myLinkId").click(functionIWantToCall);

var functionIWantToCall = function(event){
    event.preventDefault(); //this one is important
    var link = $(this).attr('href');
    //some serious action
}

<a href="..." id="piclink-242" class="view foo-242"><img src="..."/></a>

$(function() {
  // using the id attribute:
  $('.view').click(function() {
    viewer.show(+/-(d+)/.exec(this.id)[1]);
  });

  // or using the class attribute:
  $('.view').click(function() {
    viewer.show(+/(^|s)foo-(d+)(s|$)/.exec(this.className)[2]);
  });
}}

$(document).ready(function()
{

$('#LinkID').click(function() {
    viewer.show($(this).attr('picNumber'));
});

});

<%= Html.ActionLink("Index", new { id = "LINKID", picNumber = 1 }) %>