Preheat oven to 375 degrees Fahrenheit. Grease two 9×13-inch pans and set aside.

In a frying pan, heat oil over medium flame. Add onion and sauté until translucent, about seven to 10 minutes. Add mushrooms and sauté for five minutes. Add red pepper and cook for another 10 minutes.

In a separate bowl, combine tuna, eggs, matzo meal, soy sauce and salt. Add vegetable mixture to tuna mixture. Combine very well.

Form mixture into 12 patties with your hands. Place in prepared pans and spray with cooking spray. Bake for 12 minutes. Remove from oven and flip. Spray with cooking spray and return to oven for an additional 10 minutes.