Prep Your Carrots. First things first, wash and peel your carrots. Now, you need to grate them. The traditional way uses a special Korean julienne peeler or grater that makes long, thin strands. If you don't have one, the julienne attachment on a mandoline or a food processor with a julienne disc works great! Or, you can just use the large holes on a box grater, but try to keep the strands as long as possible.
Combine Carrots and Aromatics. Place your beautiful grated carrots in a medium bowl. Add the minced garlic, sliced green onions, ground black pepper, and salt. Give everything a good toss with your hands (it's okay, get in there!) or a spoon to distribute the seasonings evenly.
Make the Dressing. In a separate small bowl or measuring cup, whisk together the sesame seeds, sugar, apple cider vinegar, and sesame oil until the sugar is mostly dissolved.
Dress the Salad. Pour the dressing evenly over the carrot mixture. Now, toss everything really well until all the carrot strands are coated in the vibrant dressing.
Marinate (The Important Part!). This is where the magic happens! For the best flavor, cover the bowl and let the salad marinate in the refrigerator for at least 30 minutes. Even better? Let it sit for a couple of hours, or even overnight. The flavors meld and deepen, and the carrots soften just slightly, becoming incredibly flavorful and juicy.
Serve! Give it one final stir before serving. You can adjust seasoning to taste if needed (a little more salt, sugar, or vinegar?). Serve it chilled or at room temperature.