Prepare carne asada on the grill or in the oven. (If grilling, you can marinate your steak ahead of time and grill it while the fries bake or make your carne asada in the oven and dice and pan fry to reheat just before serving on the fries.)
Preheat oven to 450˚F. Line a rimmed baking sheet with parchment paper.
Scrub potatoes and cut lengthwise into ¼-inch wide slices. (recipe note #1) Stack slices and cut into ¼-inch wide strips. Place potatoes in a large bowl and cover with hot tap water. Soak 10 minutes then drain and spread potatoes out on a clean kitchen towel and thoroughly pat dry.
Place dried potato strips in a large bowl; drizzle with avocado oil and toss to coat. Arrange in a single layer on prepared baking sheet and sprinkle with salt. Bake fries 15 to 20 minutes, until the bottoms are crisp and golden brown. Remove baking sheet from oven and carefully flip fries over and spread into a single layer; bake 5 minutes (recipe note #2). Remove baking sheet from oven and sprinkle with cheese; bake just until cheese has melted, 2 to 3 minutes more.
While fries bake, chop grilled carne asada or oven baked into bite size pieces. If using leftover or cold carne asada, cut into bite size pieces and warm over medium-high heat in a bit of hot oil in a skillet. Set aside.
To serve, arrange the fries on a serving plate (or individual plates) top with carne asada and desired toppings and serve immediately.
I prefer to leave the skin on my baked fries, but feel free to peel the potatoes before slicing if you prefer.
Before topping the fries with cheese, make sure they're just the way you want them (some people love really crispy fries!) Taste one and return them to the oven if you want them crispier and continue to bake, checking for doneness every 2-3 minutes. It's also a good time to taste for seasoning and add a little more salt if you like (keeping in mind that the cheese is salty too).
Note that nutrition information does not include optional toppings.