I would use a salad spinner.
You can use centrifugation to separate liquids from solids.
A salad spinner is a kitchen tool used to wash and remove excess water from salad greens.
It is a simple centrifuge that separates the water from the leaves as it spins.
In a pinch, it should also be able to remove most of your unwanted oil and vinegar from the greens.
Here's a video of a salad spinner in use.