So 2 college age americans living in japan, we had to work to come up with things to eat everyday and this became something of a specialty for us. Things you'll need:

onion
beef (or chicken or whatever I guess)
soy sauce
mirin (a type of cooking sake, you can get it at oriental markets)
sugar
rice (prefferably not long grain)
tortillas
eggs
cabbage or broccoli or whatever vegetable you think would go best. We left this out a lot of times being the unhealthy college kids we are.
butter or oil

So first you want to put on the rice so its cooking.
Then put some butter or oil in a pan and sautee the onions
Next you add the meat and vegetables
Then you pour in the soy sauce and mirin, about equal parts maybe but you can kindof find a balance of your own. You want to pour enough so theres some left over but not too much or the eggs get weird later.
After you put in the sauces, pour the sugar on top of everything, this is kindof a matter of preference but probably put in more than you think you would need too. It might take a couple tries haha.
Then cook until meat is finished and spoon it out onto the tortilla, leaving some of the sauce in the pan.
Then put an egg or two in the pan with the sauce and scramble them. theyll soak up whats left of the sauce unless theres too much in there.
Then take the eggs, meat/veggies, and rice and put it onto a tortilla. You can probably handle it from there. Enjoy! Although, no promises because it doesnt always turn out the same for me even. Might be worth trying if your by yourself one night and feeling adventureous. Sometimes ill add the eggs before i take the meat out, but then theres not a lot of sauce in the burrito. Have fun!