In medium container with lid, or in large ziptop bag, combine steak slices, mojo and 1 tsp. adobo; transfer to refrigerator. Marinate at least 2 hours, or up to 24 hours. Drain steak, discarding marinade. Bring meat to room temperature.
Heat 1 tbsp. oil in large skillet over high heat. Add onions; cook, stirring occasionally, until starting to brown, about 3 minutes. Add peppers to pan. Cook, stirring occasionally, until starting to brown, about 3 minutes more. Season vegetables with sazonador total and adobo; transfer to large serving platter. Cover vegetables with foil to keep warm.
Heat remaining oil in skillet over high heat. Add beef; cook, in batches, until brown on all sides, about 10 minutes. Transfer meat to serving platter.
To serve, spoon meat and vegetables into center of warm tortillas. Add guacamole, pico de gallo, sour cream and salsita, if desired; wrap and enjoy.
Some types of red meat, like flank and skirt steaks (used in the fajita recipe above) have distinctive lines running through them. These lines are muscle fibers and can make the meat tough to chew if not cut correctly. For the most tender slices, cut against the grain, meaning that you slice perpendicularly across the lines, not with them. Doing so breaks the tension of the fibers, making the meat extra tender.