In a salad bowl, combine the spinach, onion, radish, salt and pepper; set aside.
In a small skillet, cook bacon over medium heat until crisp. Using a slotted spoon, remove to paper towels. Drain, reserving 1 tablespoon drippings. Combine the sugar, vinegar and lemon juice; stir into drippings. Cook and stir over low heat until sugar is dissolved. Combine cornstarch and water until smooth; add to skillet. Bring to a boil over medium heat; cook and stir for 1-2 minutes or until thickened.
Pour over spinach mixture and toss to coat. Top with bacon and egg.