Prepare the Dipping Sauce: In a small mixing bowl, whisk together the soy sauce, white vinegar, olive oil, sesame oil, freshly grated ginger, and minced garlic until the mixture is emulsified. Set aside at room temperature.
Trim the Collard Greens: Wash the collard green leaves and pat them completely dry. Lay each leaf flat, carefully shave down the thick raised stem so it sits flush with the leaf, and cut a small "V" shape at the bottom to remove the most fibrous part of the stalk.
Soften the Wrappers: Heat a large skillet over medium heat (do not add oil or water). Place one damp collard leaf flat into the warm skillet, cover with a tight-fitting lid, and steam for one minute until bright green and flexible. Transfer to a cutting board and repeat for all leaves.
Assemble the Filling: Lay a softened leaf flat. In the bottom third of the leaf, place two cooked shrimp, followed by a small handful of cucumber, carrots, and bell pepper matchsticks. Top with two thin slices of avocado. Do not overstuff.
Roll with Confidence: Fold the bottom edge of the collard leaf tightly over the filling. Fold the left and right sides inward, holding them in place, and continue rolling upward firmly. Place seam-side down on a serving platter.