Mince the garlic and cilantro. Add all of the ingredients with the chicken inside a plastic ziploc bag and massage the spices into the chicken. Make sure it's coated properly and leave in the fridge to marinate for 30 minutes - 1 day.
Heat the one tablespoon of olive oil in a hot skillet and add the chicken thighs. Cook 4-5 minutes on each side until cooked through.
Transfer to a chopping board and slice.
Slice the peppers and onion.
In a large skillet, add the 2 tbsp of olive oil and add the sliced onions and peppers. Cook for 2-3 minutes until they start to soften. Add the taco spice with the water and cook until the water has completely evaporated. Turn off heat and set aside.
Slice the tomatoes and avocado. Chop the romaine lettuce.
In a large plate or bowl, add the lettuce, tomatoes and avocado. Top with the cooked peppers and onions. Add the sliced chicken thighs.
Pour the cilantro lime dressing all over the salad and enjoy!