Bucatini with Fresh Tuna

Name: Bucatini with Fresh Tuna
Ingredients: Kosher salt; 2 tablespoons extra-virgin olive oil; 12 ounces fresh tuna steak, cut into 1/2-inch chunks; 1/2 red onion, cut into 1/2-inch chunks; 1 small bulb fennel, cored, trimmed and chopped, plus 1/2 cup fronds; 3 stalks celery, chopped, plus 1/2 cup chopped leaves; 3 tablespoons drained capers; 1/2 teaspoon dried oregano; 1/4 teaspoon red pepper flakes; 1/3 cup dry white wine; 1 15-ounce can cherry tomatoes; 10 ounces bucatini or spaghetti