That “dish” I brought in for the potluck was nothing more than a jar of quick-pickled red onion and green beans. A bright, refreshing, not to mention gut-friendly addition to any salad, burger, or bowl, pickled fruits and veggies are as versatile as they are easy. To make them, I start with a Mason jar filled with a cup of water, a cup of apple cider vinegar, and about 1 to 2 teaspoons of salt. Depending on what I’m cooking…