One of the key open questions in high energy astrophysics is understanding how black holes act as powerful cosmic engines, accreting large amounts of material and expelling matter in the form of relativistic jets. Time-domain observations now offer a promising new way to address this question. Through detecting and characterizing rapid flux variability in black hole systems across a wide range of frequency/energy bands, we can measure properties that are difficult, if not impossible, to measure by traditional spectral and imaging methods (e.g., size scales, geometry, jet speeds, the sequence of events leading to jet launching). While variability studies in the X-ray bands are a staple in the community, there are many challenges that accompany such studies at longer wavelengths. However, through utilizing the unique ability of the VLA to operate in sub-array mode, we can manufacture the data-sets we need to overcome these challenges. In this talk, I will discuss exciting new results from fast radio timing observations of several black hole X-ray binary sources. With this work, I will highlight how we can directly connect variability properties to internal jet physics, deriving fundamental jet properties from time-series signals alone. Additionally, I will discuss a new global observing program aimed at obtaining more of these invaluable fast timing data sets, and the key role that next-generation instruments (e.g., ngVLA, SKA, JWST) will play in driving new discoveries through this science.