Cook beans to tender/crisp: Add beans to large skillet or Dutch oven. Add about 1 cup water and desired amount of salt. Bring to a boil, cover, and reduce to a simmer. Cook four to five minutes until tender/crisp. Drain and plunge into a bowl of cold water. Drain when cool and set aside.

Add the vinegar, oil, sugar, salt, and celery seed to a large bowl. Whisk to mix and dissolve sugar (the sugar doesn’t need to be completely dissolved.) Taste and adjust, adding more vinegar, sugar, or salt as desired. The dressing should be both sweet and tart and well seasoned with salt.

Add the green, wax, and kidney beans along with the onion. Stir to coat. Cover and refrigerate, preferably overnight to serve the next day. Stir occasionally if time permits.

Notes:

• Canned wax beans and/or green beans may be used in a pinch.
• Will keep for about a week, tightly covered in the refrigerator