Preheat oven to 425 degrees Fahrenheit (220 degrees Celsius).

Rinse salmon fillets and place on a broiler pan. Combine teriyaki sauce, ketchup, and sugar in a small mixing bowl. Smear half the mixture over the salmon; place in the oven and bake for 25 minutes.

While the salmon is baking, bring six cups water to a boil; add ramen noodles, salt, and oil and cook for three minutes (or according to package instructions). Remove from heat, drain, and return to pot. Pour remaining half of the teriyaki mixture into the pot, reserving a bit for drizzling over the salad, if desired.

Spread lettuce over a large platter (you can also plate this individually). Pour ramen noodles over the lettuce and spread to cover most of the lettuce. Using two forks, break salmon into small chunks; divide over the noodles.

Scatter sliced tomatoes on top, if using, and drizzle with remaining sauce, if desired.