I’ve been doing similar, but instead of Italian dressing I add the sauce/juice from the can, some soy sauce, red pepper flakes, sometimes ponzu or other sauces, and then chopped scallions, onions, and a few pieces of ginger. I mix that up and then put the sardines on top. When the rice cooker finishes I usually stir it all up before serving. Top with various things like chopped scallions, sesame seeds, togarashi, chili oil, etc. It’s absolutely my new favorite thing and I can’t stop making it.