The last time my mom and I made once-a-month-meals she showed me this great tip for quickly slicing olives in half. And no, we didn't hire a hand model. My mom's hands are just that pretty.
You will need:
two Tupperware lids
large knife (you need a knife long enough to reach across the middle of the Tupperware lid)
Begin by placing one Tupperware lid on the counter, top up. Pour olives on top. the lip of the Tupperware helps hold olives in place.
Place the other Tupperware lid on top of the olives, face side down.
While gently holding the top lid on, slide knife through horizontally.
We were able to slice half a can at a time.