Readings & Meanings:
I chose and bought a ripe avocado.
I'm running for office in the election.
He was chosen to be an athlete in the marathon.
選 has the Shinnyou or Road Radical, the left and bottom framing radical that stems from 辵 (movement).
巽, though its meaning is "southeast" through borrrowing, is a pictograph of two people lined up (the backwards S's on the top) with a pair of hands (a form of 廾).
So the combination is, line people up to choose which one to go with.
大統領選 means "presidential election," but cuts off the kyo of 選挙.