There was an old Gourmet recipe for white bean salad with tuna - very few ingredients, everything shone. Iirc tomatoes, a bit of onion, the beans, and good canned or bottled (in oil) tuna. Maybe parsley. A light dressing. Delicious.
ETA: Maybe this one? Though I’m sure it was mid-late 90s. Skip the cucumber, add some red onion, and let the beans marinate in the dressing for a bit before you add the tuna.
My favorite way with flageolets: sauté allium(s) of choice in olive oil, add whole thin-skinned cherry tomatoes till they burst, add halved and sliced endive, add drained cooked flageolets and herb of choice (I like thyme), heat through. Serve topped with chopped celery leaves or finely chopped celery. Fantastic with lamb in any form.
Speaking of rancho gordo - that was the 2nd part of my Chanukah wish list (besides spices from B&B). They got me 8 lbs. I cooked the red ones into a red beans and rice w/andouille. Then black garbanzos! which were used in multiple ways. Hummus, bean/kale/ham soup, and veg enchilada casserole for school lunches. I’m surprised at how toothsome the beans are after much cooking. And the black on the garbanzos was a bit odd. It’s on the skin only, so once they were blended, everything became oddly grey. Tasty though. Taking a bean break and then will resume. I like the idea of the faux tuna salad.