The chapter presents a system allowing pianists to manipulate live audio processing of the piano through microgestural hand and finger control. The system avoids the need for pianists to learn new finger and hand movements, and instead utilizes movements already present in standard piano technique, thus enabling the performer to have a greater level of control over digital sound processing through intuitive gestures. By using radar millimeter waves to capture micromotions and microgestures, performers achieve high levels of expression without the need to modify their instrument or develop additional technique. This research builds upon existing instrumental technique and removes the steep learning curve typically found when performing digital or augmented musical instruments. We present a case study that enables pianists to retain and focus on technical control and musical freedom, resulting in a less disruptive experience.