Preparation Heat onion and 1/2 cup oil (start from cold) in a large heavy pot or Dutch oven over medium. Cook, stirring occasionally, until onion is translucent, 10–12 minutes. Add tomatoes, garlic, tomato paste, 1 tsp. oregano, 1/2 tsp. red pepper flakes, and 2 tsp. salt. Cook, stirring occasionally, until sauce is thickened and most of the liquid is evaporated, 15–20 minutes. Stir in 1 cup water and bring to a boil. Meanwhile, heat 1 Tbsp. oil in a large nonstick skillet over medium-high until shimmering. Working in batches and adding more oil if needed, cook artichokes cut sides down until deeply browned on cut sides, 6–8 minutes. Transfer to pot with sauce. Add beans to pot and stir to combine. Reduce heat to medium-low and simmer, stirring occasionally, until beans are heated through and flavors have melded, about 10 minutes. Taste, and add more salt if needed. Transfer bean mixture to a large serving bowl or dish. Top with feta, oregano, and red pepper flakes and drizzle with oil. Let sit at least 10 minutes for feta to soften before serving warm or at room temperature.