Rare kaon decays belong to the class of flavour changing neutral current decays and are forbidden at leading order in the Standard Model. For this reason, these decays constitute attractive channels to look for new physics. The NA62 experiment (CERN) is starting this year to measure rare kaon decay amplitudes and it is important to have precise predictions of these quantities in the Standard Model. Some of these amplitudes are dominated by long-distance hadronic effects that can only be obtained through a non-perturbative calculation. I will present in this talk a proposal and a proof-of-concept calculation on how this can be achieved through lattice simulations.