Season the steak with salt and pepper on both sides, be liberal.
Place the steak, onion, and juice from 1 lime in a zip lock bag or shallow container, seal and place in the fridge overnight to marinate.
When you are ready to cook, heat a non stick pan, when hot, add the steak, cook to your desired doneness.
Place steak on a cutting board and cut into thin strips across the grain.
Lay out a large flour tortilla, pile on some steak along the middle of the tortilla, but keep it away from the sides.
Top steak with sour cream and or guacamole as desired.
Fold one side of the tortilla over the middle, fold in the sides, continue rolling.
Continue making burritos for the amount of steak you have.
Serve and enjoy.