[SalesForce] Selecting Fields on a related record component of lightning Page

Ok, I found it after doing some serious reading of the Winter '16 release.

You need to implement the interface:

force:hasRecordId

in your component and then you can access the record id via the following expression

{!v.recordId}

An example component would be:

<aura:component controller="CTRL_F_Controller" implements="flexipage:availableForAllPageTypes,force:hasRecordId">
<aura:attribute name="Account" type="Account"/>
    <ltng:require styles="/resource/bootstrap"/>
    <div class="bootstrap-sf1">
       <div class="container">
           <ui:outputText class="form-control" aura:id="recid" value="{!v.recordId}" />
        </div>
    </div>
</aura:component>

The beauty of component framework is events .You can make two components talk to each other via events .All you need to do is handle the event when the case record is created in another component and use Navigation to redirect to needed page

Here is sample component you need to create for that

Create a component like below

<aura:component implements="forceCommunity:availableForAllPageTypes">
  <aura:handler event="force:navigateToSObject" action="{!c.navigate}"/>
</aura:component>

The handler controller logic for same is as below

({
 navigate: function(component, event, helper) {
  var sobjectId = event.getParam("recordId");
    console.log(sobjectId);
    if (sobjectId.indexOf("500") >-1) { //Note 500 is prefix for Case Record
        var urlEvent = $A.get("e.force:navigateToURL");
        urlEvent.setParams({
            "url": '/case/'+sobjectId,
            "isredirect" :false
        });
        urlEvent.fire();
    }
  }
})

Drag this component on the case creation screen using community builder .