This is going to sound like it's more trouble than it's worth, but I promise it doesn't take as long as you'd think and is exceptionally good at getting rid of leftovers.
You'll need:
You're going to be cooking this in two stages. Preheat the oven to 400 degrees. Throw some olive oil in a pan on medium heat. Add minced garlic and a chopped onion along with the spices listed above. Cook the onions until they're translucent. Throw in a small chunk of butter (don't bother using margarine; use butter in this one or don't use it). Crank the heat all the way up until the butter melts, add a largish splash of white wine and lime juice. Turn down the heat. Let the sauce reduce.
While that's happening, slice your bagels in half and spread pasta sauce over the top; don't be stingy.
Once the onions are done (when the wine has cooked away) spoon them on top of the bagels. Add grated or sliced cheese to the top - it's important you add the toppings in this order: the sauce keeps the bread moist and gives the onions something to stick to while the cheese holds it all together.
Throw your bagel halves into the oven (preferably directly on the rack; a cookie sheet will be alright too but don't use tin foil - foil conducts heat away too quickly and causes condensation on the top of it. The object is to have toasted bagels, not soggy ones.) Let them cook for 10 minutes or so. You want the cheese to be melted, the sauce to be hot and the bottoms of the bagels to be crispy. When they meet those criteria, remove them. Let them cool.
Eat. You can even add some hot sauce if you like but it's really not necessary; if you're dying for a little kick, throw some crushed red pepper in with the other spices or use a spiced pasta sauce.
You can, of course, do this the extremely simple way - slice bagels, top with sauce and cheese, throw in the microwave and nuke until the cheese melts - but there isn't much special about that, now is there?