Herbed Bean Salad

Soak onion in cold water, 10 minutes.

Meanwhile, whisk Dijon and vinegar in a bowl. Slowly whisk in oil until combined. Drain onion and dry well. Stir into dressing along with beans and herbs; season with salt and pepper. Let sit 15 to 20 minutes or refrigerate in an airtight container up to 5 days. Serve as a side, over meat and fish, on toasted rustic bread, or mixed into greens.