Add to beans and liquid in pot. Add more water if necessary. Add rest of ingredients except salt and cook about 2 hrs, or until nearly tender. Add salt and cook until tender. Refrigerate several hrs, or overnight before serving.
Place slices in bowl and toss with salt.
Spread out on several thicknesses of paper towels to drain for 30 min. Combine vinegar, garlic, and oregano. Gradually whisk in oil. Add zucchini, onions, beans, and olives. Refrigerate, covered, at least 30 min. and up to 4 hrs.