Step 1

Stir all ingredients in small bowl. Season with salt. DO AHEAD Can be made 1 day ahead. Cover and chill.

Step 2

Line large dinner plate or pie dish with plastic wrap to prevent meatballs from sticking to the surface. Gently mix all ingredients in large bowl. Using moistened hands and scant tablespoonful for each, roll meat mixture into 1-inch meatballs. Arrange on plate. DO AHEAD–Can be made 1 day ahead. Cover and chill.

Step 3

Toss first 5 ingredients in medium bowl. Let stand at room temperature 1 hour, tossing occasionally.

Step 4

Preheat oven to 300°F. Heat sesame oil in large skillet over medium-high heat. Add half of meatballs. Sauté until brown and cooked through, turning meatballs often and lowering heat if browning too quickly, about 15 minutes. Transfer meatballs to rimmed baking sheet. Place in oven to keep warm. Repeat with remaining meatballs.

Step 5

Cut each baguette or baguette piece horizontally in half. Scoop out the inside of each piece of bread. Spread hot chili mayo on both sides of bread. Arrange jalapeños, then cilantro, on bottom halves. Top with 1/4 of meatballs. Drain pickled vegetables; place atop meatballs. Put top halves on each sandwich.