You can’t, directly. The point of generics is to provide compile-time type safety, where you know the type you’re interested in at compile-time, and can work with instances of that type. In your case, you only know the Type so you can’t get any compile-time checks that any objects you have are instances of that type.
You’ll need to call the method via reflection – something like this:
// Get the generic type definition
MethodInfo method = typeof(Session).GetMethod("Linq",
BindingFlags.Public | BindingFlags.Static);
// Build a method with the specific type argument you're interested in
method = method.MakeGenericMethod(typeOne);
// The "null" is because it's a static method
method.Invoke(null, arguments);
If you need to use this type a lot, you might find it more convenient to write your own generic method which calls whatever other generic methods it needs, and then call your method with reflection.