I know you're all "herp derp leidenfrost", but it there's a) Not enough saliva to sustain it for that long, b) it would cool down to the point that it would no longer be effected by the Leidenfrost Effect. Frankly, it's probably just a wierd mix of liquids.
Concrete could be true or faked.
Hand hammer is easily possible, he's hitting it with the heel of his hand.