This recipe calls for Morton kosher salt, which differs in shape and coarseness from other brands. If using a different brand of kosher salt, you'll want to weigh out 1 ounce, rather than measure in tablespoons. As turmeric can stain light-colored counters, cabinets, and some cookware, take care when working with this brine.
2 lb. pickling cucumbers, scrubbed and sliced 1/4" thick (about 6 cups)
2 small sweet onions, halved and thinly sliced (about 3 cups)
2 Tbsp. Morton kosher salt
4 cups ice cubes
1 1/4 cups apple cider vinegar
3/4 cup sugar
1/4 cup water
2 tsp. yellow mustard seeds
1 1/2 tsp. ground ginger
1 tsp. ground turmeric
1/4 tsp. red pepper flakes, or more to taste
1 (3/4") piece ginger, peeled and thinly sliced (optional)