Creamy, starchy, salty, crunchy, cheesy -- here's plenty of proof that plain white can be every bit as thrilling to the taste buds as it is to the eyes.
Make sauce: Stir vinegar, lime juice, mirin, sugar, red-pepper flakes, and salt in a nonreactive bowl. Let stand 15 minutes to infuse; strain. Refrigerate, covered, in a nonreactive bowl until ready to use, up to 3 days.
Make summer rolls one at a time: Submerge a rice-paper wrapper in warm water until soft and translucent, 30 to 45 seconds. Lay on a board; cut off 1 inch from left side (for top of roll). Lay about 6 pieces of cucumber, 6 pieces of daikon radish, and 4 pieces of tofu across the wrapper, placing one end at cut edge. Add scant 1/4 cup noodles, 1 mint or basil leaf, and about 8 enoki mushrooms (sticking out 1 inch). Roll wrapper tightly; trim right side level (for bottom). Transfer to a tray; cover with a kitchen towel while assembling remaining rolls. Refrigerate summer rolls, covered, until ready to serve, up to 2 hours. To serve, stand rolls on end, with mushrooms pointing up. Serve with sauce.