Place soaked wheat berries in a large pot, fill with water, and bring to a boil. Reduce heat, and simmer until tender, about 35 minutes. Drain, rinse under cold water, and drain again.
Combine vinegar and orange juice and zest in a small bowl. Pour in oil in a slow, steady stream, whisking constantly until emulsified.
Combine wheat berries, celery, walnuts, and dates. Stir in vinaigrette and teaspoon salt. Season with pepper.
If you don't have time to soak the wheat berries overnight, do a quick soak: Put them in a pot of cold water, and bring them to a boil. Remove from heat; let stand, covered, for 1 hour, and drain.