In a saucepan, bring water and rice vinegar to a boil. Remove from heat; cool for 2 minutes. Combine carrots and daikon in a heat-safe container. Place cucumbers in separate heat-safe container. Divide jalapeño slices between the two containers.
Add 1/2 tbsp. Vietnamese x Cajun Seasoning to each container. Divide hot vinegar mixture evenly between the two containers. Let stand at room temperature at least 30 minutes before serving.
In a bowl, whisk egg, buttermilk, mustard, and 1 tbsp. of the Vietnamese x Cajun Seasoning. Add shrimp, tossing to coat well. Marinate shrimp 30 minutes in refrigerator.
In a bowl, mix flour, cornmeal and 1 tbsp. Vietnamese x Cajun Seasoning. Dredge marinated shrimp in dry mixture. Shake off excess. Let stand 10 minutes before frying.
Fry shrimp at 350°F until golden brown and cooked through, about 3 minutes. Remove from fryer and toss shrimp in remaining Vietnamese Cajun seasoning.
Spread 2 tbsp. of Vietnamese x Cajun Remoulade on each roll. Top with 4 oz. of cooked shrimp per sandwich. Top with tomatoes, lettuce, pickled cucumbers, pickled carrots and daikon, and cilantro.
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