I solder leadless microcontrollers like the 28 pin QFN PIC18F2520 with a Weller heat gun and some no clean flux. Just put a teeny amount of solder on all the pads, position the IC, weight it down with an insulated pair of pliers, and use the heat gun.
I keep it about 3" off the PCB and slowly move it in circles until the solder melts and the IC drops down onto the PCB surface. Afterwards I allow it to cool, then test for shorts, although it’s pretty rare. If I do find any, I simply reheat the IC and PCB again and it typically takes care of the problem.