There is no dedicated Multi-Look tool. Conventional multi-looking is merely pixel averaging at the expense of lower spatial resolution. Using Radar Utilities > Radar Speckle Suppression (optional step) followed by Degrade is a comparable alternative. Then you must use the SAR Metadata Editor to add the SAR metadata back on.
The InSAR Wizard workflow does have multi-look as a processing step which is done to reduce noise and prepare the image for Unwrap. So one could process the data thru to that Step and use that intermediate product.
