That`s merely pressurized butane fuel (lighter fuel) being sprayed on the inside of the tye and set alight. The resulting rapid ignition (explosion) of the air inside the tire causes it to inflate. See here.
The little 12V mini air compressors that run off your lighter socket are great for getting air pressure backup when you have a slow puncture. It usually takes a good 10 mins for the air pressure to get high enough to drive on, but for slow punctures I`d rather do that, than mess about with the spare. I`ve always left the re-sealent stuff alone, as for me, it offers no advantage. Once the air pressure is back, as long as the wheels are rolling the air stays in so I usually over fill the flat tire abit with the mini-compressor and then drive to the closest tire center.
Oh, and it seems the price of a 12v mini-compressor is lower in Sri Lanka than it would be abroad, so I`d buy from a local retailer instead of going through the hassle of importing one or getting one off ebay.