Lightly wet your fingertips and palms.
Form a walnut-sized amount of prepared sushi rice (about 2 tablespoons / 30 ml / 1 fl oz) into a rectangular mound with a flat bottom.
Repeat to create 12 mounds in total.
Using a mandoline, carefully slice the cucumber lengthwise into very thin, wide ribbons. The first few slices may be too small; you'll need 12 long slices wide enough to stand taller than the rice mounds when wrapped.
Wrap one cucumber slice snugly around each rice mound to create a boat wall. The ends of the cucumber should overlap and stick to each other. Avoid using the seedy center slices.
Divide the roasted peanuts evenly among the boats, placing them on top of the rice.
Add a tiny dab of grated daikon and ginger on top of the peanuts.
Garnish with a sprinkle of togarashi and thinly sliced green onion.
Serve with Sweet Chili Sauce for dipping the bottoms of the boats.
Keep your hands slightly damp when handling the sushi rice to prevent it from sticking to your fingers.