Set a large skillet over medium heat. Put two small bowls and four serving bowls on the counter so they are ready when you need them.

Finely grate the yellow outer peel from the lemon into one small bowl. Cut the lemon and squeeze 2 tablespoons juice into the second small bowl, then cut the rest into wedges for serving.

Add 1 tablespoon olive oil and the panko to the skillet. Cook for 3 to 4 minutes, stirring often, until the crumbs are evenly golden brown.

Transfer the toasted crumbs to a plate. Stir in 1/4 cup of the Parmesan and 2 tablespoons of the parsley while the crumbs are still warm.

Make the dressing in the bowl with the lemon juice. Whisk in the Dijon mustard, 2 tablespoons olive oil, 1/4 teaspoon of the salt, and 1/4 teaspoon of the pepper until smooth.

Put the skillet back over medium heat. Add the remaining 1 tablespoon olive oil.

Add the chopped shallot to the skillet. Cook for 2 to 3 minutes, stirring often, until it softens and no longer looks raw.

Add the drained beans to the skillet. Stir for 1 minute so they are coated with the oil and shallot.

Use the back of a wooden spoon to lightly crush about 1 cup of the beans right in the skillet. Leave the rest whole for texture.

Add the baby spinach to the skillet with 2 tablespoons water. Sprinkle in the remaining 1/2 teaspoon salt and the remaining 1/4 teaspoon pepper.

Stir the spinach into the beans and cook for 1 to 2 minutes, until the spinach wilts down and the water cooks off.

Add the drained tuna to the skillet in large pieces. Gently turn it through the bean mixture so it warms without breaking up too much.