1) If there in only single commandLink in the form, you could specify it the enclosing form level as given below:

<h:form id="form1" target="blank">
...
<h:commandLink action="#{mybean.myaction}" id="link" value="Click here to open new window">
</h:commandLink>
...
</h:form>

2) If there are multiple commandLink tags in the enclosing form, you could use onclick attribute to navigate in a new page:

<h:form id="form2">
...
<h:commandLink action="#{mybean.myaction1}" id="link1" value="Click here to open new window1" onclick="javascript:window.open('#{request.contextPath}/myview.1jsf');">
</h:commandLink>
....
<h:commandLink action="#{mybean.myaction2}" id="link2" value="Click here to open new window2" onclick="javascript:window.open('#{request.contextPath}/myview2.jsf');">
</h:commandLink>
...
</h:form>