When beans are cool, drain and lay full length on a platter with stem ends together. With a hand at each end of the beans, pull them close together to form a log. Remove 4 beans and slide each under the log, equally spaced. Loosely tie each of the 4 beans over the log to hold it together.
In a small bowl, mix soy sauce with sesame oil and pour over beans.
To serve, cut across bean log between tied beans to make 4 bundles. With a wide spatula, transfer beans to plates.