Peel tomatoes by dipping them in boiling water for about 30 seconds; slip skins off. Cut tomatoes in half horizontally. Over a bowl lined with a sieve, seed tomatoes, catching and reserving juice. Cut each tomato half in two. In a food processor, in batches if necessary, puree tomato, cucumber, red onion, and shallot. Stir in reserved fresh tomato juice, canned juice, olive oil, vinegar, and chipotle peppers. Stir in Shrimp, beans, avocado, and salt. Chill at least 3 hours to marry flavors. Serve cool but not icy.