Ahi Tuna Summer Rolls

For the pickled carrots and daikon, using a knife or a box grater with a julienne blade, cut (or grate) the carrots and daikon into a thin julienne about 1/8 inch thick and 2 to 3 inches long.  

In a medium pot, combine the water, vinegar, sugar and salt and bring to a simmer over medium-high heat. When the sugar dissolves, remove from the heat. Add the garlic, ginger, jalapenos, onions, carrots and daikon and submerge the vegetables under the pickling liquid by covering them with a small plate. Let steep for at least 15 minutes at room temperature. Remove 1 cup of the drained carrots and daikon mixture, pat dry and set aside for the summer rolls. Once cool, store the remaining vegetables and pickling liquid, tightly covered in the refrigerator, for another use.  

Bring a medium pot of water to a boil for the rice noodles. 

Meanwhile, make the seasoned fish sauce. In a medium bowl, whisk together all the ingredients. Pour into 4 small bowls for serving. 

For the summer rolls, when the water comes to a boil, season with salt. Drop the rice noodles in the water and cook, stirring occasionally, until soft but still springy, 5 to 8 minutes. Drain the noodles in a colander and rinse with cool water to remove any starch and to cool the noodles. 

Assemble the summer rolls. To soften the rice paper wrappers, fill a large tray with at least a 2-inch-high rim with cool water. (The tray needs to be large enough to fit the rice paper wrappers.) Submerge a rice paper wrapper in the water for about 1 second; it will immediately begin to hydrate. Transfer it to a cutting board or clean work surface. Gently rub the water into the wrapper with your hand; it will soften and start to develop a little starch on the surface in about a minute. When the wrapper feels tacky and soft (but not too soft or it will break), you can start to add the fillings.  

On each wrapper, place ¼ cup of the cooked rice noodles 1 ½ inches from the bottom edge. Top the rice noodles with 2 to 3 leaves of butter lettuce and fold 1 inch of the left and right sides of rice paper inward. Take the bottom of the wrapper and do a quarter roll toward the top of the wrapper so that the noodles and lettuce are covered on all sides with rice paper. Make sure there still is 2 to 3 inches of rice paper left to roll. 

Add a small handful of the pickled carrots and daikon, 2 sprigs of cilantro or the leaves from 2 sprigs of mint and 3 to 4 slices of tuna. Finish rolling the wrapper—it will stick to itself at the end to hold the summer roll together. Repeat with the remaining ingredients. 

Garnish the summer rolls with the salmon roe and chia seeds (if using) and serve with the seasoned fish sauce for dipping.