I grow a lot of okra each summer and have never run across what you are describing. Is this something topical that can be removed prior to or after harvesting the okra? Does it do the okra any harm or is it just ugly in appearance?
From what you are describing, it sounds a bit like insect eggs of some sort or it could be insect poop like you mentioned. Are the leaves showing signs of damage like some type web or cut worm attacking them?
I've had cut worms leave their droppings on plants and it is similar to very tiny peppercorns in appearance. If it were me, I'd take a flashlight and head out at night to see if something is on the plants at night. Some insects only do their damage when dark.