No idea if a squirrel can be trained to do things they don't ordinarily do but I know they can be taught to fly ... I've seen ithem on the telly.
Joking aside, a few years ago whilst at Thorpe park I saw a squirrel jump from a small tree straight onto a swing bin, after a few seconds it regained it's composure and balance and then put it's weight on one side of the lid so it would open and he dropped into the bin.
A few seconds past and his little head appeared from under the lid peaking out as though he was on the look-out, when he jumped out I saw he had what looked like a piece of burger bap or similar, as soon as he knew the coast was clear he scurried back into the tree he came from.
Not a great story I know but it was fascinating watching him, they kind of remind me of foxes, bin chickens (aka seagulls) .... opportunists with excellent survival skills using it's surroundings for easy pickings.