Combine ingredients for steak marinade into gallon sized zippered bag. Add sliced steak. NOTE: If you slice the steak when it's slightly frozen, you can get thinner and more uniform strips. Let marinate in refrigerator for at least 4 hours (up to overnight).
Combine ingredients for spicy mayo. Transfer to squeeze bottle if desired.
Add enough oil for ½ inch depth in a saute or frying pan. Heat to 350degF.
Add cornstarch to zippered bag with marinating steak. Smoosh around evenly coat and combine. Once oil is hot, start adding individual strips to oil in batches and fry for 45-60 seconds on each side. Remove to wire rack over paper towel covered pan. Repeat until all steak is fried.
In another frying pan over medium high heat, toast up each side of each tortilla for about 45 seconds.
Build the taco by add portion of coleslaw mix and red onions to toasted tortilla. Next put 4-5 strips of crispy beef. Drizzle with spicy mayo and garnish with cilantro and jalapenos.