Every time I make rice paper rolls I use new types of filling, because for me is important to use what I have stored in my fridge. I will try to do my best to explain how to wrap and how to combine the different kinds of vegetables.
What you must do to create the perfect wrap: Rice paper (large size). Vegetables shredded or cut into smaller sizes, all kinds of lettuce leaves (the red is a bit bitter.) To wrap containing sliced avocado, mango or yellow red beet I use rice vermicelli noodles, which is a thin type of rice noodles. For the stuffed rice-paper I use sometimes fried BBQ tofu, if you want to try something new and crispy.
You can make small wraps, cut into bite-sizes, filled with shredded vegetables or the larger cut vegetables if you want a whole roll, to dip into the sesame sauce.