Fill a deep pot with water over high heat and bring to a boil. Add the corn cobs. Boil until the kernels are tender, approx 4-7 minutes depending on the age of the corn. Fresher corn will cook faster. Drain and allow to cool so you can handle them. Using a sharp knife, cut the kernels from the cob and set aside.
Pour the oil into that same pot, leaving at least 1/3 head space. You only need a couple inches or so. Place over medium-high heat. The oil is ready when you drop a a cube of white bread in the oil and it browns in 30 seconds. If it browns faster, turn down your heat and as always, have a fire extinguisher near by whenever you fry. I don’t want you to burn your house down. If it takes longer than 30 seconds, wait and try again in a couple minutes.
Once the oil is hot, you can shallow fry the tortillas to make them super crispy and golden. Carefully place the tortillas in the oil, one or two at a time depending on the size of your pot (don't over crowd them) and fry about 45 seconds per side. Drain on paper towels and season with salt and smoked paprika. Set aside until all tortillas are done.
When the tortillas are almost finished, heat a cast iron pan over medium-high heat. Season both sides of your fish well with salt and pepper. Drizzle a little oil in the pan. When nice and hot (but not smoking), place the seasoned fish in the pan. Sear only long enough to create a nice brown colour on the outside of the fish; you want your tuna raw in the middle. Flip, do the same on the second side. It will only take a minute or two per side, tops. Remove from heat and let sit for a minute or so. With a very sharp knife, cut against the grain into 1/4" slices. Set aside.