Prepare the rice. Pour water into a saucepan and add rice. Bring to a boil over high heat. Reduce heat to medium. Cover the saucepan with a lid. Cook the rice for another 10 minutes. Remove from heat and let sit for 10 minutes.
Make the rice dressing. In a small saucepan or saucepan, combine the rice vinegar, sugar, and 1 teaspoon warm (not hot) water. Heat and stir until smooth.
Assemble Philadelphia rolls at home using a step-by-step recipe. Take a mat and wrap it well in cling film. Place a sheet of nori on it with the shiny side down. Put rice on top and smooth it over the surface of the nori. Turn the nori over with the rice down and put the filling: cream cheese, cucumber, avocado. Roll the roll into a tight roll, and carefully spread the fish slices on top.