Place 1 tablespoon canola oil and all but the fish in a large resealable bag; shake to combine. Add halibut and squeeze out as much air as possible, seal, place on a plate and refrigerate for 30 minutes.
Heat remaining canola oil over medium-low/medium heat in a large non-stick skillet. Remove fish from marinade. Add to pan and cook until dark golden brown and a paring knife inserted into centre of fish for 10 seconds comes out warm, about 8 to 10 minutes, flipping halfway.
Serve topped with slices chilies and cilantro and accompanied with Herby Lime Tartar Sauce.