Prep all ingredients per the instructions above.
In a bowl, whisk together olive oil, lime juice, garlic, cumin, crushed red pepper flakes, honey, and cilantro. Add the chicken and coat well with the marinade. Refrigerate for at least 30 minutes.
Make the guacamole: In a bowl, mash the avocado until smooth. Stir in cilantro, garlic, cumin, and lime juice. Season with salt. Refrigerate until ready to serve.
Preheat a grill or grill pan to medium-high heat.
Grill the chicken on both sides to an internal temperature of 160°F (74°C). Remove from heat and let rest for 2 -3 minutes before slicing or shredding.
Warm the tortillas: Heat a dry skillet over medium heat. Warm each taco shell for 20 seconds per side until soft and pliable.
Assemble the tacos by filling the taco shells with chicken, black beans, lettuce, cheese, and avocado.
Pour sparkling water over lime slices and serve with ice if desired.
Serve tacos with tortilla chips, guacamole, and lime sparkling water.