Snip the ends off green beans where the bean attached to the vine.
Prepare ice water bowl by combining cold water and a couple of cups of ice in a large mixing bowl.
Bring a large pot of water to boil and drop green beans in it. Boil them for about 2-4 minutes (depending on thickness).
Take green beans out of the hot water and immediately into the ice water.
After green beans have cooled, take them out onto a clean towel to pat dry.
Sauté Green Beans:
Preheat a large cooking pan over medium heat.
Slice bacon strips, width-wise, into small, thin strips. Slice onion thinly as well.
Spread bacon in the hot pan and sauté for a couple of minutes, until bacon fat is half way rendered and bacon starts to brown.
Add onions and sauté until onions are softened and start to brown.
Add green beans and season with a little bit of salt and pepper.
Sauté green beans for 10-15 minutes, mixing from time to time. Cook time will depend on how soft or crunchy you prefer green beans.
Notes
Make Ahead: You can easily blanch the green beans a day ahead or even longer. If you blanch green beans the night before, make sure to pat them dry and store them in the refrigerator in an airtight food storage container.
Storing: store leftover green beans in an air-tight food storage container, in the refrigerator, for 2-3 days.
To reheat: sauté them in the preheated pan for a few minutes, just until heated through.