You kinda got the idea of Okizeme wrong. Okizeme is the idea of you having advantage or a mix-up game on your opponent and taking full use of it since the opponent will have limited options on the floor. It is not the attack that will force them to block check.
Basically, off any knockdown you can set oki-setups, however, there's some creative ways some characters can create Oki's. For instance, Smoke can do his normal combo into air throw, however instead of pure damage, he can cancel the launcher into a smoke port, which will reset the character and put him in a left/right high/low mix-up immediately after.
Oki's aren't the attack, but the general setup mixup that comes (usually referring to an opponent on the ground).
