Prepare the onion. To prevent the red onion from tasting very sharp, place it in a small bowl of cold water, add 1 teaspoon (5g) salt and let it soak for 5-10 minutes. Drain it well and pat dry. Feel free to prep your marinade while waiting on the onions.
Combine the base ingredients. Place the white beans in a large mixing bowl. Add the red onion and chopped sun-dried tomatoes. Toss gently to distribute everything evenly.
Make the marinade. In a small bowl or measuring cup, whisk together the olive oil, lemon zest, lemon juice, garlic, Dijon mustard, maple syrup, salt, and black pepper until well combined and slightly emulsified.
Dress the beans and add the herbs. Pour the marinade over the bean mixture. Add the parsley, basil, thyme, and red chili flakes. Using a spoon or silicone spatula, gently toss until the beans are evenly coated. Mix carefully so the beans stay mostly whole.
Marinate. Cover the bowl and let the beans marinate for at least 1 hour at room temperature if serving the same day, or refrigerate for 4 hours or overnight for deeper flavour.
Serve. If chilled, let the beans sit at room temperature for 15-20 minutes before serving so the olive oil loosens and the flavors open up. Taste and adjust with a little extra salt, lemon juice, or olive oil if needed.
