For an extra-elegant touch, press a whole nasturtium flat against the rice paper wrapper before rolling. The flower will show through the translucent wrapper. The marigolds here are Tagetes erecta.
1. To make Sauce: Whisk together vinegar, brown sugar, soy sauce, and cornstarch in saucepan. Stir in garlic and ginger, and bring to a boil. Reduce heat to medium-low, and simmer 3 minutes. Cool; stir in green onions.
2. To prepare Rolls: Cook mung bean threads according to package directions. Drain, rinse with cold water, drain again.
3. Fill 9-inch round cake pan with 1 inch hot water. Soak 1 wrapper in hot water until softened. Transfer to work surface, and pat dry. Arrange 3 Tbs. bean threads over center of wrapper. Top with 1 Tbs. each carrot, cucumber, and bean sprouts, then 2 tsp. green onions, 1 tsp. marigold, 1 tsp. nasturtium, 1/2 tsp. mint, and 1/2 tsp. cilantro. Fold bottom of wrapper over filling, fold in sides, and tightly roll up, burrito-style. Repeat with remaining wrappers and filling. Serve with Sauce.