Buried onions similes in book

Answer 1

1 simile can be: with sweat weeping off my brow, i jabbed the shovel into the ground where a fancy flower bed would go and let it stand like a spear.

smile is comparing two unlike things by using (like or as)

one example from buried onions is

the swamp coolers squeaked like squirrels.

the author comparing swamp coolers by squirrels and the both are two unlike things .

Answer 2

The onions symbolize the town's unexpressed emotions, particularly of hopelessness, anger, and grief.