A possible solution could be:
class Container
{
public List data{get;set;}
}
class IdField
{
public string id{get;set;}
public string field{get;set;}
}
string s1 = "{ \"data\": [{ \"id\": \"id1\", \"field\": \"field1\" }], \"paging\": { \"prev\": \"link1\", } }";
string s2 = "{ \"data\": [{ \"id\": \"id2\", \"field\": \"field2\" }], \"paging\": { \"prev\": \"link2\", } }";
var d1 = JsonConvert.DeserializeObject(s1);
var d2 = JsonConvert.DeserializeObject(s2);
d1.data.AddRange(d2.data);
var result = JsonConvert.SerializeObject(d1);