1/2 cup sherry vinegar
6 tablespoons capers with juice
6 heaping tablespoons spicy mustard
6 to 7 shallots
3 cups olive oil
2 cups chopped radicchio
2 cups chopped watercress
2 cups chopped fresh mint leaves
2 cups chopped cucumbers
2 cups diced tomatoes
2 cups crumbled feta cheese
1/2 cup pitted and chopped kalamata olives
2 cups chopped scallions