It would be kind of a pain to just dab the right amount of solder paste onto the small pads so I would probably end up ordering a stencil too from oshstencils.com.
Depends on how many you want to solder onto your newly created breakouts. For prototyping one usually needs only one or two. Hardly worth a stencil. Also with such small parts, cheap manufacturers sometimes screw up with HASL pads. They tend to fuse them together when coating. I've had to wick up excess solder from some osh and dirtypcb boards. My process to get the solder paste onto the pads is:
1.) Get toothpicks and dip them into the paste (paste in a small pot)
2.) Look at the paste whiskers at the tip
3.) Adjust paste's viscosity with solder flux
4.) Repeat steps 1-3 until the whiskers are thin enough for the pads
5.) Apply thinned paste whiskers to pads
It's nothing you want to do for hours, but for two or three chips it's less of a hassle than a stencil and much cheaper.
To avoid overheating, ensure there is a sufficiently good thermal path from the IC. "Sufficiently good" includes the PCB layout, construction and size. The manufacturer will often give guidance.
On page 13 of the
datasheet. I wonder what the via under the pad means to accomplish. Usually I'd say its bad style because it decreases contact area and might make problems when soldering. As I said, the package will have to dissipate 0.6 W tops if you're insane enough to pass 31A through it. It can take 125 deg C (85 for the K variant). So even at a six times crappier board design than they quote, its temperature won't exceed the 125 C (ambient 24 C + 6 * 24C/W * 0.6W ~ 114 C - 4* for the K). For most applications, thermals won't matter much for this chip. Of course you don't want to push it to its limits nor fry a steak with your board when the summer is hot. Also dependability, accuracy and longevity correlate with temperature. All I'm saying, you'll need to work hard to screw up thermals for this chip.