This salad can be prepared and refrigerated up to 4 hours in advance. Bring to room temperature before serving.
Servings: Serves 6–8
Ingredients 1 pound dry beans (white, navy, or cannellini)1 1/2 teaspoons kosher salt , plus more to taste1/2 teaspoon freshly ground black pepper , plus more to taste2 cloves garlic , minced1 tablespoon Dijon mustard2 to 3 tablespoons white wine vinegar1/3 cup extra-virgin olive oil6 plum tomatoes (about 1 pound), chopped1 small red onion , dicedCanola or grapeseed oil , for frying1 bunch sage
Place beans in a large pot and fill with just enough water to cover. Simmer until beans are tender, 1 to 1 1/2 hours. Just before they're done cooking, season beans with 1/2 teaspoon salt and 1/4 teaspoon pepper (if you season any sooner, skins of beans may split and centers may harden). Drain, if necessary and transfer to a large bowl.
Meanwhile, with a mortar and pestle, crush garlic and remaining 1 teaspoon salt until a paste forms. Add mustard and mix well. Add vinegar. Gradually whisk in olive oil until a smooth emulsion forms. Pour mixture over beans while still warm. Add tomatoes and onion; toss to coat and set aside.
Pour in enough canola or grapeseed oil to cover the bottom of a large skillet and place over medium-high heat until oil is very hot but not smoking. Add sage leaves in 1 layer, sprinkle with salt and fry lightly until crisp, about 2 minutes. (If leaves are crowded, fry in batches.) With a slotted spoon, remove to a plate covered with paper towels; let drain.
Sample salad and adjust seasoning to taste. Sprinkle with sage leaves just before serving.