Heat oil in a large heavy pot over medium. Cook onion, stirring occasionally, until golden and softened, 8–10 minutes. Add garlic and red pepper flakes and season with salt. Cook, stirring often, until fragrant and garlic is softened, about 2 minutes. Add tomato paste and cook, stirring occasionally, until slightly darkened in color and starts sticking to bottom of pan, about 4 minutes. Add wine and cook, stirring often, until the smell of the alcohol is almost completely gone, about 4 minutes. Add tomatoes and juices, crushing with your hands, and increase heat to medium-high. Cook, stirring often, until sauce thickens slightly, 8–10 minutes. Taste and season sauce with salt.