How to Make It
In a large bowl, combine 2 tablespoons of the lime juice with 1 teaspoon of salt, stirring to dissolve the salt. Add the chicken thighs and turn to coat. Refrigerate for 2 hours.
In a food processor, combine the tomatillos, garlic, serranos, onion and cilantro and process to a coarse puree. Transfer the salsa to a bowl and stir in the avocado and the remaining 2 tablespoons of lime juice. Season with salt.
Pat the chicken dry with paper towels. In a shallow bowl, combine the flour with the pepper, cayenne and 1/2 teaspoon of salt.
In a large skillet, heat 1/3 inch of oil until shimmering. Dredge the chicken in the flour, shaking off any excess. Fry the chicken over moderately high heat until well-browned and crisp, about 3 1/2 minutes per side. Transfer to paper towels to drain.
Cut the chicken into thin strips and serve with the tomatillo salsa and warm corn tortillas.
Zimmern likes trimming away some of the chicken thigh so there's as much crispy skin as there is meat. If you opt to do the same, fry the chicken for 3 minutes per side.