Position a rack on the top level of the oven, about 4 inches from the broiler. Turn on the broiler.
Line a rimmed baking sheet with aluminum foil.
Place the tomato halves on it, cut side down. Broil until the tomatoes are softened and slightly charred (10-12 minutes). Allow to cool to room temperature.
Combine 4 quarts water, 1/4 cup lime juice and 2 tablespoons salt in a large saucepan and bring to a boil over high heat.
Add the shrimp and cook until they are fully cooked (about 3 minutes) . They should be bright pink-orange, curled and firm but not hard.
Immediately drain the shrimp into a colander and hold under running cold water for about 1 minute. Drain well, transfer to a bowl, cover and refrigerate until cold.
Combine the roasted tomatoes, the remaining 1/2 cup water, the remaining 2 tablespoons lime juice, the adobo sauce, the honey, the garlic, the Worcestershire sauce and the pepper in a blender and puree on high speed until smooth. Season to taste with salt.
When ready to serve, pour the sauce into a large ceramic or glass bowl. Add the shrimp, avocado, cucumber, onion, diced tomato, cilantro and jalapeno. Stir gently to mix.
Serve in tall glasses or sundae glasses with long spoons and accompany with the crackers. Pass the lime wedges at the table.