I've been making this for years and never with a recipe. You can too: the amounts given here are just guidelines. It's fresh, easy, filling, and quick enough to throw together in the morning to take to work.
1 cup cold cooked rice (any kind)
½ cup firm tofu, diced
1 sheet nori
1 tsp soy sauce
1 tsp rice vinegar
½ tsp roasted sesame oil
½ cup cucumber, diced
chopped chives, green onions and/or sesame seeds, for garnish
Toss the rice and tofu together with the soy sauce, rice vinegar, sesame oil, and a few grinds of black pepper. Taste the mixture, and if you think it needs more of anything, add more. Now cut the nori up into little strips with scissors, right on top of the mixed salad, and mix this in very gently—it's nice if the nori stays a bit crispy. Top with the cucumber and anything you're using as a garnish (but it doesn't absolutely need a garnish). Serve immediately or refrigerate.