Peel the plantains; this is done easily by slicing 2-3 slits down the length of peel so you can peel it apart. Slice the plantains thinly with a mandolin or by hand, diagonally, so it creates more surface area. Toss plantains with the rest of the ingredients (oil and spices).
Preheat your air fryer to 374F.* Bake for 15-20 mins, shaking every 5 mins or so and removing any chips that are already browned and crispy.
Meanwhile, prepare the guacamole. This can be done in a food processor, but I prefer to make it by hand. Finely chop the onion and cilantro leaves. Mash the avocados with a fork in a bowl, and then combine with all other ingredients. Taste and adjust seasoning (salt, lime juice, pepper) as needed.
Notes
*To bake the chips in the oven, preheat the oven to 400F and bake for 15-20 mins, flipping the chips halfway through.