Cut ends off oranges, then cut off peels and outer membranes and discard. Slice oranges 1/2 inch thick, then cut into cubes, discarding seeds. Place in a bowl.
Pit, peel, and dice avocados; add to oranges. Add cucumber, onion, lime juice, and chipotle purée and salt to taste; mix gently.
To make chipotle chile purée, whirl the contents of a 7-ounce can of chipotle chiles (including sauce) in a blender or food processor until smooth. Scrape into a plastic container and store airtight in the refrigerator for up to 3 weeks.