Home alone for 2 weeks, I ordered a pizza 2 days ago, ate 3 slices, and have a big 'ole bunch of leftovers. So, trying to decide what to do with them, I came up with the following idea, which came out really well:
1, Take 2 slices of pizza, preferably the same size. They should be cold, e.g., right out of the fridge.
2, Take any toping you want on the pizza in addition to what's already there. It probably won't work with too much stuff, but you can put a fair amount on. I grilled some salami and used that, but diced chicken or leftover sausage or whatever. Oh, try to make sure whatever it is isn't particularly wet--it'll just get sloppy.
3, You'll need a Panini press. I have this one which I like because it's got a flat plate. A grill-like one will work here too. Get it nice and hot first.
4, Take slice one, the larger of the two if they're not equal sized and put it face up on the bottom of the press, put your toppings on top of this, and put the second slice upside down (cheese down) on top of the first.
5, close the press and let it cook.
As the pizza heats, the griddle will crisp the top and bottom at the same time as it slowly heats the middle and melts the cheese, goo-ing up the toppings together. This is a knife and fork meal, but it's damn good.