In a saucepan, combine soy sauce, sugar, lemon juice, and fish sauce over medium heat. Stir until the sugar dissolves, then bring to a gentle boil for about 2 minutes. In a small bowl, mix tapioca starch with water and stir into the saucepan to thicken the dressing. Remove from heat and set aside to cool.

Choose your protein. For chicken or beef, bring a pot of water to a boil and blanch for 5-7 minutes until fully cooked. For tofu, pan-fry until golden and crisp. Slice or shred the meat and keep warm.

Bring a large pot of water to a boil, add rice noodles and cook according to package instructions (4-6 minutes). Drain and rinse under cold water. Toss with a drizzle of oil and refrigerate.

While the noodles cool, wash and prepare vegetables and herbs. Thinly slice or julienne cucumbers, carrots, and cabbage. Chop fresh herbs and store everything in separate bowls.

Combine cooled rice noodles and dressing in a large bowl, tossing to coat. Layer in your choice of protein, chopped vegetables, and herbs. Mix together until well-combined. Serve immediately.