Combine ingredients for burger sauce, mayo, mustard, relish, grated onion, paprika, onion powder, garlic powder, and white vinegar. Place in the fridge for later.
Season ground beef with salt, pepper, and garlic pepper and mix to combine.
Divide ground beef into 8 evenly sized portions, approximately 2 oz. each.
Place each portion of meat onto a tortilla, pressing it flat to spread it until it covers the entire tortilla surface, right up to the edge.
Heat a large cast iron skillet or griddle over medium high heat.
Place smash burger into skillet, meat side down. Cook for 3 minutes, without moving until a good crust has formed on the meat. The size of your pan will dictate how many you can cook at once, but do not overcrowd the pan.
Flip burger and place slice of cheese on top of the cooked meat. Lower heat and allow cheese to melt 1-2 minutes. Take care that the tortilla does not burn.
Repeat with remaining smashed tacos.
Once all are cooked through, top with diced onions, shredded iceberg lettuce, pickles, and special sauce.
Fold up like a taco and enjoy!