Lay your cilantro on the cutting board. Give it a quick rinse. Pat it dry. Wet cilantro is slippery and clings to the knife. Dry cilantro is a team player.
Now, grip the knife. Place your other hand flat on top of the blade (knuckles away from the edge!). Rock the knife back and forth. Don’t just stab at it. Rock and roll. Chop until you get tiny, confetti-sized pieces.
Stop chopping when it looks like green sprinkles. Over-chopping turns it into a mushy paste. Unless you want cilantro paste. In that case, go wild. But for most of us, sprinkles are the goal.