Diablo – Does Cyclone Strike have some kind of hidden stun

Under the Skills menu, mouseover the skill's image and hold Ctrl. This will expand the tooltip to show detailed information. This also works in the skill selection menu and the hotbar.

There is also an option to show detailed information by default. Go to Options > Gameplay and check the Show Advanced Tooltips option.

From my observation (with my crit wizard), the crit is calculated individually and with separate chance. You can hit 2 enemies at the same time, and each of those have a separate crit chance. You can tell because a yellow number will pop on one of them and not the other sometimes.

For example, one-handed weapons would clearly be better for such builds, since critical strike frequency is higher with them.

Indeed. Some additional tips :

1. Instead of pure damage, choose a weapon that has attack speed. The end dps include this extra speed, but you'll hit a lot faster for the same damage.

2. Dual wield. Having two weapons means hitting faster. Having two weapons both with attack speed bonus is even better.

3. Builds based on critical chances have good affinity with life steal. Additionally since you're going for an attack speed build, often life per hit is more beneficial than pure life steal %.