Slice cucumber very thin. Use a mandolin (use caution) slicer for best results. Remove excess moisture from slices using a paper towel.
Put cucumber slices in a large bowl and toss with oil, vinegar, and salt. For dehydrator: Place slices on trays and dry at 125-135°F for 10-12 hours or until crispy.
For oven: Place slices on parchment lined baking tray. Dry at 175°F for 3-4 hours or until crispy. Allow slices to cool before serving.