Bring a large pot of salted water to boil and cook the soba noodles just until al dente, according to package directions. Rinse them under cold water, drain, and return them to the pot. Toss the noodles with the sesame seeds and toasted sesame oil. Set aside.
Meanwhile, make the dipping sauce: In a small bowl, whisk together the almond butter, vinegar, tamari, honey, lime juice, sesame oil, ginger, garlic, and pepper flakes until well combined. If the sauce is too thick for dipping, stir in a little more lime juice.
To prepare the spring rolls: Run a julienne peeler or vegetable peeler down the length of the carrot and cucumber repeatedly, turning halfway, to create long "noodles." Toss the carrot and cucumber with the soba noodles.
Fill a shallow pan larger than your rice papers (a pie pan works great) with warm water. Fold a lint-free towel in half and place it next to the dish (I just used a plastic cutting board). Make sure your prepared fillings are within reach.
Place one rice paper in the water and let it rest for about 20 seconds. You'll learn to go by feel here--wait until the sheet is pliable but not super floppy. Carefully lay it flat on the towel.
Leaving about one inch of open rice paper around the edges, cover the lower third of the paper with a handful of soba, carrot and cucumber noodles. Top with a few strips of jalapeño and avocado in a row on top of the noodles, then sprinkle with green onions and chopped cilantro.
Fold the lower edge over the fillings, then fold over the shorter sides like you would to make a burrito. Lastly, roll it up, stretching the remaining long side around the roll to seal it. Repeat with the remaining ingredients. Halve the rolls on the diagonal with a sharp chef's knife (or serve whole) with the almond butter dipping sauce on the side.