Cut the tuna into chunks about a 1" cube and lay onto a baking sheet covered with parchment paper. Cover the tuna with plastic wrap and place the sheet of tuna into the freezer for about 15 minutes to get very cold.
Also put a medium ceramic or glass bowl in the freezer. You will use this cold bowl to mix the tuna with the other ingredients.
Add to a food processor the onion, ginger, jalapeño, garlic, mayonnaise, olive oil and sesame oil and pulse until combined together. The mixture will be slightly chunky and not completely smooth.
Remove the ingredients from the processor (no need to clean it) and place in a small bowl. Keep this bowl in the refrigerator until ready to mix with the tuna.
Remove the baking sheet from the freezer and place half of the tuna into the processor and pulse a few times until it looks like ground hamburger. Add the ground tuna to the cold bowl from the freezer and then repeat with the remaining tuna.
Add the small bowl of ingredients to the bowl of ground tuna and mix gently with a spatula until all the ingredients are combined.
Preheat the grill to medium high heat.
Make 5 patties each about ½" thick and season both sides with salt and pepper.
Brush the grill or grill pan with some olive oil so that the patties will not stick.
Grill the patties for about 2-3 minutes on each side.
Enjoy!