Prepare the rice noodles by boiling them in water for 2-3 minutes according to package instructions. Drain and rinse under cold water to stop the cooking process. Set aside to cool.
In a bowl, marinate the beef slices with 1 tbsp soy sauce and garlic for 10 minutes.
Heat a skillet over medium-high heat and add vegetable oil. Sear the marinated beef for 1-2 minutes per side until browned but not fully cooked. Let the beef rest for a few minutes, then slice thinly and let it cool.
In a serving bowl, combine the cooled rice noodles, seared beef, cucumber, and carrots.
In a separate small bowl, whisk together soy sauce, chili garlic sauce, honey or maple syrup, rice vinegar, and sesame oil to create the dressing.
Pour the dressing over the noodles and toss well to coat evenly.
Garnish with chopped scallions, cilantro, and toasted sesame seeds if using. Serve chilled, optionally with a squeeze of lemon juice.