>>2772036If you can't get them fresh (I hate tinned/jarred ones), just use quartered okra. Same prep process (soak, drain and fry).
You might have to soak in several changes to remove the mucus as much as I like it removed; the snotty nature of cactus leaves and okra is a turn-off for me, but I love the flavour.
Another thing I like is to fry up the cactus leaves in olive oil with capers and pit-in gaeta olives.
In lieu of either, just use green bells. The texture will be different but that's okay.