Toasted sesame oil transforms a humble staple like canned tuna into an elegant supper. We love the crunch of napa cabbage in this salad, but romaine lettuce would also work if you happen to have that on hand.
Whisk vinegar (or lemon juice), canola oil, soy sauce, sesame oil, sugar and ginger in a small bowl.
Combine 3 tablespoons of the dressing with tuna, peas and scallions in a medium bowl.
Divide cabbage among 4 plates. Mound one-fourth of the tuna mixture (about 1/2 cup) in the center of each plate and garnish with radishes, cilantro and sesame seeds. Drizzle with the remaining dressing (about 2 tablespoons per salad) and season with pepper.