Start by making the sauce. In a small bowl, combine the mayo, ketchup, sweet relish, yellow mustard, white vinegar, sugar, paprika, garlic powder, and onion powder. Mix well and set aside.

Divide the ground beef into 12 equal portions, about one small handful each, and shape them into balls.

Place a mini flour tortilla on a flat surface and put a ball of ground beef on top. Flatten the beef until it covers the tortilla's edges in a thin layer. Sprinkle with a pinch of salt and pepper.

Heat a pan over medium-high heat and add 1/2 teaspoon of vegetable oil. Place the tortilla with the meat side down in the pan. Use the back of a spatula or a burger press to press down, creating a smashed burger effect. Cook for 3-4 minutes until the ground beef is browned.

Flip the taco over so the tortilla side is down. Place a slice of cheese on top of the beef and allow it to melt for about a minute.

Remove from heat and top with diced onion, shredded lettuce, pickles, and a drizzle of the Big Mac sauce. Enjoy your taco while it's still warm!