Interactive lenses have proven to be useful for many visualization applications where exploratory analysis is a primary task. Up to now, interaction with lenses is mostly limited to single-user, single-function lenses operated by mouse, keyboard and traditional parameter menus. To overcome these limitations, we propose MultiLens, touch-enabled magic lenses for fluently manipulating functions, parameters, and combinations of lenses on interactive surfaces. We contribute a novel multi-touch menu technique for magic lenses using a widget-based approach with a drag-snap slider for relative parameter adjustment. We also propose a continuous gesture set for rapidly changing lenses and their primary parameters in one seamless phrase. In addition, by supporting the combination of various lens functions, we create a generic multi-purpose lens tool. We illustrate our approach by investigating and implementing the concepts for the field of graph exploration. The prototype was evaluated in a user study with 22 participants comparing it to traditional parameter menus operated with both mouse and touch.