It's really easy to know the threshold voltage of the MOSFET using Cadence.
Step1: Construct a correct circuit, whatever, maybe a inverter and perform the TRAN analysis.
Step2: Results->Print->Transient Operating Pionts
Step3: Click the MOSFET of which you want to know the threshold voltage in your schematic.
Then a window with all kinds of parameters, one of which is vth, will pop out. I hope it would be helpful.
Another way is as Paul Gray mentioned in his famous book. You can perform the DC anlysis and obtain the sqr(ID) vs VGS to find the threshold voltage. Pay attention to the fact that the threshold voltage HAS something to do with the dimension of your MOSFET.
Threshold voltage is just for reference. It's unnecessary to invetigate the exact value because the process corner will give you something really differnt from your simulation result.