Pulse onion in a food processor fitted with an S blade until it is chopped finely.
Scrape chopped onion into a large mixing bowl and repeat the chopping process separately with the carrots, celery and spinach until all are finely chopped and added to the mixing bowl. For best results, chop spinach 2 cups at a time.
Add almonds and teriyaki sauce to the chopped vegetables, stir to mix well and set aside.
Slice cucumber and avocado into long thin strips and set aside.
How to Assemble
Fill a large bowl with warm water and set it next to a large plate.
Submerge one spring roll wrapper in the warm water for about 20 seconds and then place the wrapper on the large plate.
Place 2-3 tbs of the chopped vegetables in the center of the wrapper.
Add 2 slices of cucumber and 1-2 slices of avocado
Carefully fold front of wrapper over the veggies and then fold the sides over and roll forward to wrap the back and seal the roll.
Place the spring roll on a plate and repeat steps 2-5 with the remaining wrappers.
Serve immediately (with some additional teriyaki sauce for dipping if desired) or cover with a damp paper towel and store in a sealed container in the refrigerator for later.