Here's one I made earlier lol .....
Brontosaurus Craft 
you can adapt the principal to any dinosaur, providing it has a head & body
!!
With precut/torn shapes - the younger children could hand paint on them and then once dry assemble into the puppet.
Alternatively - have them paint smear with their hands onto a table surface and then take prints with the dinosaur templates. The stippled effect on the paper is wonderful!