Soak beans in warm water for an hour or more. Drain. Set a sauté pan on medium heat with butter. Add beans and enough broth to just cover the beans. Add bay leaf and a pinch of salt and bring to a boil. Lower heat and simmer with lid just slightly ajar for about 40 minutes, or until the beans are very smooth and cooked all the way through but still holding their shape. Do not rush this, an under-cooked bean is a starchy and unpleasant thing. Add liquid as the beans as they absorb the broth, adding water when you run out of broth. When they are cooked through, they should have absorbed all the liquid, if not, cook them for the last minute with top off to let the liquid evaporate.
At this point, I would take the urchin out of the fridge. It will taste best at room temperature.
Pull apart chicory and frisée leaves into small pieces, wash and spin.
Squeeze Meyer lemon juice and maple syrup into a small bowl and whisk with olive oil until you get a nice thick dressing.
Chop tarragon and chives.
Plate beans and sprinkle with Tarragon. Do not feel compelled to add all the ingredients, this is a delicate dish so I would plate sparsely and bring the extra beans to the table in a separate covered dish if your guests want seconds. Lightly dress salad greens with vinaigrette, sprinkle with sea salt and cracked black pepper. Pile the greens on top of of the beans, and carefully add your uni to the plate. They are delicate so do this gingerly.
Sprinkle chives on top and around the edge of the plate. Serve with a nice piece of toast.