Place romaine lettuce, kale, red cabbage, radish, and diced pickle in a large mixing bowl.
Place all Dill Pickle Dressing ingredients in a food processor or blender. Run machine until all ingredients are puréed. The dressing will be a light bright green from the fresh dill. Use a piece of lettuce or kale to taste the dressing. Add salt if needed.
Drizzle ½ cup of dressing over salad to start. Mix salad with dressing until ingredients are well-coated. Add more dressing as needed.
Scatter fresh dill and crumbled feta over salad right before serving.
Store leftover dressed salad in a tightly covered container in the refrigerator for up to one day. Leftover dressed salad will take on a softer, marinated texture. Store leftover undressed prepped (i.e. washed, dried, and chopped) salad greens in the refrigerator for three days. Leftover Dill Pickle Dressing will keep for three days in a tightly sealed container in the refrigerator.