In a large pan of boiling salted water, cook the potatoes over high heat until tender, 15 to 20 minutes. Drain the potatoes, rinse them in cold water, and drain them again. Set the potatoes aside to cool.
Place the bell pepper, radishes, eggs, pickles, pickle juice, and scallions in a large bowl. Chop the cooled potatoes into bite-size chunks and add them to th