To store leftover salmon quiche, allow the quiche to cool completely, then wrap tightly with plastic wrap and store in the refrigerator for up to 3 days. To reheat the entire quiche, bake in preheated oven at 300℉ for about 20-25 minutes, or until warmed through. If heating just one piece, I have found warming the slice of quiche in a dry cast iron skillet, covered, over medium-low heat for 5-6 minutes to be an effective way to crisp up the bottom crust and gently heat the egg through. Do not re-heat salmon quiche more than once.