Prepare all ingredients as instructed.
Season the potatoes with black pepper and half of the taco seasoning.
Place the potatoes in the air fryer and cook at 400°F (205°C) for 18–20 minutes, tossing halfway through, until crispy and golden.
While the potatoes cook, brown the ground beef with the remaining taco seasoning in a skillet over medium-high heat, breaking it up into pieces until nicely browned (add a splash of water if the pan looks too dry). Stir in the beans until warmed though.
Combine the sparkling water and lemon slices. Serve over ice, if desired.
Portion the crispy potatoes and beef. Top with shredded cheese, salsa, shredded lettuce, and avocado. Serve with hot sauce and/or a squeeze of lime, if desired, and lemon sparkling water.