what is the best method of checking electrical circuits for resistance points without contact?

You only have true resistance in DC circuits. In Ac curcuits, you have resistance from the dc component, and something called inductive reactance from the ac component. Both resistance & inductive reactance is measured in a unit called an "ohm". By the way the unit of conductivity is called the mho"

One instrument you can use to measure resistance & inductive reactance is a VOM (Volt Ohm Millameter)

You can pick up a cheap one from Radio Shack for something like $ 15-$20.

If your objective is to find out undesired resistance in electrical power circuits without contact, the best solution would be an infrared thermometer. Resistance contact leads to heating caused by I squared R losses. This abnormal temperature rise will show up in undesired resistance contacts in electrical power circuits.

There are current-measuring devices that can accurately measure the current in electrical circuits without ever coming into contact with them. If you know what the current should be, and your current measurement is less, then you've found resistance in the circuit.