Dice the chicken breast into small cubes and season evenly with cumin, smoked paprika, sea salt, and black pepper.
Heat a non-stick skillet over medium heat and add the olive oil to coat the surface.
Sauté the diced onion and minced garlic in the oil until they become fragrant and translucent, about 3 minutes.
Add the seasoned chicken to the skillet, browning the pieces on all sides for approximately 5 to 6 minutes.
Pour in the water and a squeeze of lime juice, then cover the pan and simmer for 3 minutes until the chicken is tender.
Remove the lid and increase the heat slightly, allowing the liquid to evaporate so the chicken develops golden, crispy edges.
Warm the corn tortillas in a separate dry pan or over an open flame until they are soft and pliable.
Divide the crispy chicken carnitas between the tortillas and top with sliced avocado, fresh cilantro, and an extra squeeze of lime.