Forgot to add salt to rice before cooking. How can I add salt after cooking to fix that?
Seems there is no need to cook rice with salt, at least in my country or my friends who love the culinary.
But if you really need some salty flavor in your rice, maybe you could:  


Turn your rice into fried rice, seasoning in the end.  
Make some yummy sauces and add onto your rice.  
Dissolve salt in water to become a salty solution, spray it on your rice and reheat again.  


Hope this would let your rice more flavored :P