In a cold saucepan, combine the olive oil, red pepper flakes, salt, and garlic, then set over medium-high heat. Stir with a wooden spoon as it heats and, once it starts to sizzle, cook just until everything is fragrant without browning the garlic, 45 seconds or so.
Stir in the tomatoes and heat to a gentle simmer, about 2 minutes. Remove from the heat, carefully taste, and add salt as needed.
Stir in most of the lemon zest, saving a bit to sprinkle. Serve with any pasta you like.
