Cut bell peppers into thin strips and onions into thin slices.
Put meat a ziploc bag or dish and pour 1/2 of the marinade over the top. If you're using 2 lbs of meat, you may want to pour a little more marinade.
Put vetables in a separate ziploc bag and pour remaining marinade over the top.
Put both in the refrigerator and chill for 1-2 hours. IMPORTANT- There are a lot of acidic components to this marinade; it's important it does not sit too long or the meat will start to break down too much.
After marinating, preheat a heavy bottom pan on the stovetop to medium heat. Dump the bag of meat first and cook until all liquid has cooked off and the meat is seared and brown.
Remove the meat and leave the browned bits in the bottom of the pan. Add the vegetable bag and scrape the bottom of the pan. The liquid from the vegetables allows you to easily scrape up the extra bits on the bottom of the pan. This adds a lot of flavor to the dish.
Once the vegetables are cooked and all the liquid has evaporated, remove from heat.
Put your meat and vegetables on a tortilla (I recommend homemade flour tortillas-recipe linked below!) and top with whatever you like. My suggested toppings are sour cream, salsa, cilantro, cheese, guacamole, pico de gallo.
Finish with a squeeze of lime juice and enjoy!