To prevent the cooked sushi rice from becoming sticky, lift and fluff it while adding the rice vinegar. Spreading the rice on a cold pan helps cool it quickly.
Look for whole wheat roll-ups in the deli section of the grocery store rather than with the flour tortillas. They are specifically designed for sandwiches and are softer and more flexible than tortillas. However, large spinach or other flavored flour tortillas can be substituted for the roll-ups. Trim 1 1/2 inches from top and bottom edges to form a rectangle.