Place shrimp, cucumber, corn, and red onion into a large mixing bowl and toss together.
Pour tomato juice and lime juice over the shrimp mixture and gently fold together.
Cover and refrigerate mixture for 30 minutes. Fold in avocado and lightly season with salt and pepper.
Scoop mixture into 4 cups, spooning any extra liquid over each cup. Top with a light sprinkle of queso fresco and serve with saltine crackers.
