- 2 cucumbers, peeled
- 1 bunch radishes, thinly sliced
- 5 scallions (white and light green parts only), thinly sliced on the diagonal
- 1/4 cup fresh cilantro leaves
- 3 tablespoons rice vinegar
- 2 teaspoons toasted sesame oil
- kosher salt and black pepper
- 4 teaspoons canola oil
- 3 teaspoons whole coriander seeds
- 2 teaspoons whole black peppercorns
- 4 6-ounce tuna steaks (about 3/4 inch thick)
- Working over a medium bowl, use a vegetable peeler to create long, thin strips of cucumber.
- Add the radishes, scallions, cilantro, vinegar, sesame oil, and ¼ teaspoon each salt and black pepper and toss. Cover and refrigerate.
- Heat the canola oil in a skillet over medium-high heat. Using the flat of a knife or the bottom of a pan, crush the coriander seeds and peppercorns.
- Sprinkle 1 ¼ teaspoons salt over the tuna and press the crushed spices onto each side.
- Cook the tuna, turning once, until it reaches desired doneness, about 3 minutes per side for medium-rare.
- Divide the tuna among individual plates and serve with the slaw.