While not strictly "faces," Chicago used fruit and vegetables in the "Heritage Floor" surrounding the table in "The Dinner Party". The floor is a mosaic depicting female figures from history, each with a unique "vagina" symbol made from different fruits and vegetables.
It's important to note that while this is a very well-known example, there may be other artists who have used fruits and vegetables in their collages in a way that depicts faces. This is a creative concept, and it's possible to find various artistic interpretations of it.
If you're looking for specific artists, you can try searching online for terms like "fruit and vegetable collage faces" or "fruit and vegetable art" and see what comes up!