Assemble the sandwiches with the bread, mayo, ham, cheese and lettuce. Using a round cookie cutter, cut the sandwiches into 3-4 circles to be used as the caterpillar (critter) body. Stand each circle upright and "glue" together with a small amount of hummus.
Halve the apples and use one half for each head. If desired, eyes and a smile can be formed from a thin slice of apple, again using hummus for "glue".
Slice the cucumber. Quarter the slices to use for the antennae and legs.
Serve critter sandwiches with any remaining critter "parts" as a side.