Step 1In large bowl, mix 1 cup of warm water, the vinegar, sugar and salt until dissolved. Add the carrots and daikon and marinate for about 1 hour (or longer, up to 2 days, for more flavor).
Step 2Slice the baguette into 4 (6-inch) sections and halve each lengthwise.
Step 3On each of 4 baguette halves, spread 1 teaspoon mayonnaise and one-half tablespoon pate.
Step 4Add 1 to 2 whole sardines to each sandwich. Mash the sardines, spreading the fish across the baguette with a fork.
Step 5Add 1 tablespoon of pickled carrots and daikon, a few slices of cucumber, several mint leaves, a few sprigs of cilantro and jalapeno slices as desired to each sandwich. Sprinkle with soy sauce and top with the remaining sliced baguette. Serve immediately.