Fig.: to criticize someone or something harshly and find faults with them

Their alibi was so weak that the police could easily pick it to pieces in no time

Il loro alibi era talmente debole che la polizia lo ha smontato in men che non si dica

When he decided to run for mayor, he expected criticism from his opponents, but he certainly did not expect the press to tear his private life to shreds

Quando ha deciso di candidarsi per la carica di sindaco, si aspettava delle critiche da parte dei suoi oppositori, ma non si aspettava di certo che la stampa facesse a pezzi la sua vita privata

In this expression pick is used in the sense of pierce or poke, which goes back to the 1300s. The phrase itself dates from the mid-1800s