First aid for dried bonsai is immediate soak the pot in a tub of water for at least several hours. Just watering from above is not enough to properly wet dry soil.
Then continue care (with much better attention to watering) until the tree responds with new shoots.
From the photo it looks like you have caught this in time and most branches still look healthy. It should recover well.
Cutting dead leaves or pruning branches will not help. The dead ones are already dead and any live parts will still be alive. Cut back in a few weeks when new shoots have started to grow and it is clear what parts are dead. The tree will manage dead leaves all by itself.