Normally you can right click your portrait to change loot spec and raid types....
Same with your target - you cant right click on them to inspect/whisper/invite...anythiing.

Am i missing something or is this not possible with Spartan?

How can i access this menu to change raid/loot specs?

Thanks.

Right click on your health/mana/castbar. The portrait can be disabled or overlayed on top of your bars so it is not part of the clickable area as it would cause issues.