Make the marinated veggies. Place carrots, daikon radish, cucumbers, vinegar, agave nectar, and salt in a medium bowl. Toss well. Set aside and let sit for 10-30 minutes.
While the veggies sit, make the egg salad. In a small bowl, mix the chopped eggs, mayo, salt, and pepper. Taste and add more salt and pepper if desired.
Half the bread, keeping one side attached. Toast if desired. Place bread under the broiler until pale golden and a bit crusty (mine takes about 1 minute). Remove from oven. Or, if you're doing a take-and-bake baguette situation, hurry and bake 'em on up!
Slather tops of bread with the remaining 2 tablespoons mayonnaise. Divide egg salad between sandwiches, piling/spreading on lower half. Top each half with pickled veggies (go ahead, load it up!) and scatter jalapeños over the top (a lot for more heat and less for ... well you get what I'm saying). Cover with cilantro and mint. Squeeze Sriracha over the top of each, if desired (a little goes a long way!)
Close the sandwich (the best you can) and slice in half. Serve immediately. Makes 4 (5-inch) sandwiches.