I know it seems really harsh but you have to ignore the tantrums. If he has been changed and is not hungry and you are sure that it is just a temper tantrum, walk away from him to show him that he can not get his way by behaving that way. I am going through the same thing with some of the children in my class, as well as my own daughter. They think that if they keep crying that you will give in and if you do, you just make them want to do it longer to get their way. This is something that I have wittnessed a lot in my few years of day care work, and let me tell you, if I had a nickle for every time a parent said that they can't stand to hear the child cry, I'd be rich! lol But after talking to them and explaining that it is just a phase and the kids have to learn what they need to do to get things, most of the parents have learned to ignore the senseless crying and tantrums.
What I do with my daughter is leave the room. As long as she is in a safe place and is not endangering herself, I go to the bathroom or bedroom (where I can still hear her and see that she is safe) and wait for her to calm down. This shows her that not only is it unexeptable to behave this way, but that it is not going to get her what she wants. When she has calmed down, she comes to me and I talk to her about it. I make sure that she knows it is not going to work.
When I am working, I make sure the child is on a soft surface (we have a tumbling mat in my room that works great for this). I make sure that the other children are not giving the tantruming child attention, and walk away. Granted I can not leave the room, but it still shows them that crying and screaming is not going to get them what they want. I tell the child,"I'm sorry that you are mad, but this is not the way to get what you want...you need to use your words or show me." I am the teacher of a toddler class that is primarily children ages 16-24 months, so we see this all time.
Hope this helps!