Cypress is naturally oily and resistant to moisture. Pure Tung Oil would complement that very well, as would one of the commercial danish oils. The thing you want to avoid is a hard-shell surface finish like polyurethane.
My go-to finish for tool handles is an oil-wax blend. Howard's Feed'n Wax is a commercial product, but its very easy to make your own by dissolving paste wax in a solvent (I prefer turpentine, but mineral spirits works also), and then blending in BLO or Tung Oil. The ratio of the components is not at all critical; some people prefer it to be a paste or cream, but I prefer it as a liquid. Looks nice, and makes the handle very comfortable in the hand. It has to be refreshed every few years, but that's simple - just wipe on some more and buff with a cloth.
