In a mixing bowl, combine all ingredients except the oil. Use your hands or a fork to make sure that everything gets fully distributed and the tuna is broken up well. I find hands more effective here.
Heat enough oil to coat the bottom of a large pan over medium high heat. Form the tuna mixture into 10 patties, flattening each slightly with your hands.
Depending on the size of your pan, gently place the patties into the hot oil (I was able to fit 4 at a time with space between). Cook for 5-7 minutes a side. If the patty seems like it is not sticking together well, then let it continue cooking for a little longer before flipping it over. They should be lightly browned on each side.
Remove to a plate to cool. Store in the fridge for 1 week.
To assemble the power bowls: divide the spinach between 4 bowls. Arrange the remaining vegetables on top, then finish it off with 1 or 2 tuna burgers. Pour a little lemon juice on top if desired.
Recipe by Lenses and Lentils at https://lensesandlentils.com/tuna-burger-power-bowls/