SMD resistors and capacitors (if you're talking about ceramic) are much more tolerant to temperature than SMD semiconductors; I was never able to damage any, and sometimes I'm pretty abusive; semis, on the other hand, were an easier task to fry...
Anyway, don't try to solder them with solder wire; instead, buy some SMD solder paste, apply a small amount on the solder points with the tip of a wooden splurge (that's what works best for me), place the resistor/capacitor over it with a tweezer and use a hot air rework tool to heat it and melt the solder. Or, if you don't have a HART, use the soldering iron tip to heat the board copper of one of the contacts until the solder melts, wait a few seconds and do the same to the other contact. This will take 2-3 seconds, which is tipically safe even for diodes. In both cases, use the lowest temperature that can still melt quickly the solder. For leaded solder, I use 390F, for lead-free 420F. Even with a soldering iron, it is essential to have a temperature-controlled one.
Finally, the smallest SMD parts I use are 0805; smaller ones are too hard to do a quick&clean job, at least in my case (obviously this may be different for you if your handling skills are better than mine).