1 Prepare rice according to package directions. While still hot, sprinkle rice vinegar over rice, and toss to combine. Set aside.
2 In a small bowl, combine tuna, mayonnaise, chili sauce, sesame oil and onion powder.
3 Take about a quarter of the sushi rice (about a scant 1/2 a cup) and press it down onto a tortilla, as if making sushi. (It may help to use a piece of plastic wrap for this, to prevent the rice from sticking to your fingers.) Spoon a quarter of the tuna mixture in a line, a little bit off center. Top tuna with vegetables, and roll wrap around the tuna-vegetable filling by folding up the bottom end and then rolling the wrap width-wise.