Divide the salsa between two 32-ounce Mason jars. In a small bowl, mash the avocado with the lime juice and salt. Spoon over the salsa. Layer the remaining ingredients in the following order: cabbage, carrots, bell pepper, cucumber, chicken, cheese (if using), and spinach. Cover with lids and refrigerate until ready to serve.
When ready to serve, pour the salad into a bowl and enjoy.