Deserialize your json collection:
Deserialize a Collection[
^]
After that, write a method that converts your deserialized objects into a datatable, and Bob's your uncle.
BTW, if you use the netwtonsoft json.net library (a nuget package), you can deserialize directly to a datatable.
DataTable dt = (DataTable)JsonConvert.DeserializeObject(myJsonString, (typeof(DataTable)));
The only possible issue is that it will deserialize all of the fields as string object.