Soak over night. Drain beans and return to pan. Add enough cold water to cover beans by 3 inches and bring to a boil. Cook corn in pot of boiling water until crisp-tender, about 5 minutes. Drain and cool.
Cut corn kernels off cobs.
Whisk vinegar and lemon juice in small bowl. Gradually whisk in oil. Pour dressing over salad and toss well. Season with salt and pepper. Heat 1 tablespoon of oil in heavy large skillet over medium heat.