Other than extra braking and reverse thrust, is there a specific short-field landing technique for large jet airliners?
Never heard of any. The required landing distance is calculated so that the plane can reliably stop (even if reversers fail) and landing at shorter runway is not allowed.
so the 747s try to land right on the numbers, rather than the usual technique of touching down within the first third of the runway.
The usual technique is to aim for 1,000 ft down the runway and touch down with some flare somewhere around 1,500.
In discussions about the famous landings at St Maarten, it is sometimes said that part of the reason for the low passes is due to the relatively short runway, so the 747s try to land right on the numbers
Actually the TNCM runway 10 has PAPI and TDZ marking a little beyond the usual 1,000 ft mark at around 1,250 ft. Ourairports says the threshold is displaced 162 ft (but it also says runway 9, so it is likely out of date), but according to the satellite images it is a bit over 300 ft plus some runway end safety area, placing the threshold around 500 ft past the fence and the touch-down zone around 1,750 ft past the fence.
Now the normal glide-slope is around 5%. That means the aircraft is supposed to cross the fence at around 90 ft, on average. That seems about right. Of course you can't expect every aircraft to be positioned precisely within a few feet, so now and then some crosses it at maybe 50 ft. That is not intention, but simply a deviation. But of course the photos of planes flying especially low are more likely to be picked for publishing.
Also, a short field landing normally calls for steep approach which make precise aim for landing spot easier. That would actually place the aircraft higher over the beach. But the glide-slope at TNCM is normal 3° (5%) one, so it is not a steep approach.
Such a procedure is fine in a Cessna, but in a large passenger jet? I have my doubts.
In large jet it isn't. Air transport has stricter regulations than general aviation because more is at stake and larger aircraft have stricter limits because the higher energies involved mean errors are harder to fix and have more serious consequences.