Use a Rice Cube to form the sumeshi into squares (or use your hands, dampened with water, to form the sumeshi into balls. Or you can use plastic wrap, or a small mold). You can layer the rice with ikura, if you’d like
Top your cube or ball of rice with one lobe of uni (or two if they’re small) or a small scoop of ikura.
Sprinkle with a little paprika and black sesame seeds, if desired.