They are supported automatically with custom JavaScript codes as long as you extends your component handle from org.zkoss.zul.impl.XulElement.

The onClick, onRightClick and onDoubleClick events are handled automatically by ZK Client Engine. All you need to do is to generate the correct attributes by use of the appendAsapAttr method.

public String getOuterAttrs() {
    final StringBuffer sb = new StringBuffer(super.getOuterAttrs());    
    appendAsapAttr(sb, Events.ON_CLICK);    
    appendAsapAttr(sb, Events.ON_DOUBLE_CLICK);    
    appendAsapAttr(sb, Events.ON_RIGHT_CLICK);    
    return sb.otString();    
}

HtmlBasedCcomponent provides an utility called getAllOnClickAttrs to simplify the job.

public String getOuterAttrs() {
    String attrs = super.getOuterAttrs();    
    String clkattrs = getAllOnClickAttrs();    
    rerturn clkattrs != null ? attrs + clkattrs: attrs;    
}