Heat a large saucepan or skillet over medium. It should have at minimum a 7 cup capacity. While the pan heats up, remove the root end and tough darker greens tops of the leeks and discard. Slice the leeks lengthwise down the middle, then slice thinly into half moons. Rinse well in a colander to remove dirt then drain and pat dry. Mince the garlic cloves. Remove the tough ends of the asparagus and discard. Chop the asparagus into bite-sized pieces (about 1-inch in size). Zest and juice one of the lemons, reserving each for later. 

Once the pan is to temperature, add the olive oil. The oil should shimmer. Once it shimmers, add the chopped leeks and a pinch of salt. Cook the leeks, stirring regularly, until they are beginning to caramelize, about 3-4 min.

Add the garlic and the asparagus and another pinch of salt and cook for 2-3 minutes until the asparagus turns a deeper green color, making sure to stir frequently to keep the garlic from burning.

Stir in the orzo and vegetable broth. If your broth is low sodium, add another pinch of salt. Raise the heat to medium high. Bring the broth to a boil, then reduce the heat to maintain a simmer. Simmer, stirring frequently, until the orzo is cooked through and al dente, about 10 minutes.

Stir in the frozen peas and cook for an additional minute, then remove the orzo from the heat. Stir in the lemon zest and juice, and the Parmesan. Taste, then add more salt or lemon juice as needed. Serve topped with more Parmesan if desired and chopped tarragon.