Heat a large pot of water and bring it to a full boil. Add the raw chicken breasts and reduce heat slightly. Cook for 8 to 12 minutes (depending on thickness of chicken), until chicken is cooked through. Place chicken on a cutting board, allow it to cool, then chop into cubes. For best results, refrigerate the chicken until chilled prior to finishing the recipe.
Add the chopped avocado, lemon juice, and sea salt to a large mixing bowl and mash everything together using a fork until creamy.
Add the remaining ingredients (including the chopped chicken) to the mixing bowl and stir well until combined. Taste salad for flavor and add more lemon juice and/or sea salt to taste.
Serve chicken salad on a bed of spinach as a green salad or on toasted bread to make a sandwich.