Left overs are not recommended as the crunchy coating will become soft and the cheese will melt in microwave.
Do not use string cheese because it is thin and will not hold its shape while frying.
It helps to keep the sausage and cheese cold until frying. Warm mozz will melt in the frying process.
Fried Korean Hot Dogs may be frozen and reheated in air fryer at 350F for 5 ish minutes. Reheating in microwave will potentially result in leaky melty cheese.