Place a peeled avocado half, cut side down, on a cutting board. Slice through the width into very thin slices and fan out into a straight line. Place on a serving plate. Bring the two ends in to create a ring. Repeat with the remaining half.
Fill the avo ring with the beans, tomatoes and coriander. Season with salt and pepper. Serve with nachos.
Tips:
Round shaped avocados work best to create a ring with the same height all over.
For a meaty variation, replace the Mexican tomatoes with bolognaise.