I have never planted onions with beans but the information I have is that onions and garlic inhibit the groth of peas and beans. I have been experimenting with companion planting for 8 yrs. and I'm interested on what you've found out.

You wouldnt want to plant the onion next to the beans put something like radishes, lettuce, next to the beans. You shouldnt have to move either out of the same bed unless really close.

Here is a link on good & bad combos of plants.

Good luck

Here is a link that might be useful: companion planting