Heat the oven to 375°F and grease a 9x13 inch baking dish.
Boil the noodles until al dente, with a firm bite and no longer. Drain, but do not rinse.
Pulling the noodles at al dente keeps them from turning mushy, since they soften a bit more in the oven.
While the noodles are still warm, toss them with the condensed soup until evenly coated. Do not add any water or milk.
Fold in the tuna and peas. Drain the peas only loosely so a little of their liquid stays in the mix.
Spread everything into the baking dish and cover with the cheddar and/or bread crumbs.
For the crustiest top, use cheese, or put the cheese down first and the bread crumbs over it.
Bake uncovered for 20 to 25 minutes, until bubbly at the edges and golden on top.
Let it rest for 5 minutes before serving.
If you'd like a little kick to this, try adding some hot sauce to dial it up.
Reheat any leftovers until hot all the way through, ideally to 165°F.