1. Pat the tuna steaks with a paper towel to remove any moisture. Brush the tuna with canola oil all over and salt and pepper each side.
2. Pulse the wasabi peas in a small food processor until it forms a course powder. Place the peas in a shallow dish for dredging such as a pie pan and mix in some black sesame seeds.  Dredge the tuna steaks on all sides in the wasabi peas powder to coat.
3. Heat a medium cast iron skillet on high heat. Add about 1 tablespoon of canola oil. Sear the tuna for 3 minutes on first side and 2 minutes on second side until nicely seared on the outside and rare on the inside. Make sure to sear the sides as well. Take out of the skillet and let rest on a cutting board for 5 minutes. Slice thinly against the grain and serve with the dipping sauce and a dollop of wasabi paste.

For the dipping sauce: Whisk together soy sauce, rice vinegar, ginger, and pepper flakes in a small bowl. Top with green onions to garnish and serve alongside tuna slices.