Preheat oven to 350 degrees.
To make the crostini slice a baguette into 1/4" to 1/2” pieces. Brush the pieces with olive oil and sprinkle with salt and pepper. Bake for about 10 minutes, flipping the toasts halfway through. Remove from oven and set aside.
Add the walnuts, basil, 2 tablespoons of olive oil, lemon zest, salt and garlic to a food processor. Pulse until a pesto forms, scraping down the sides periodically as needed.
Place the beans in a large skillet. Add in the pesto and sauté over medium heat for about 3 minutes until the beans are coated and the pesto starts to sizzle.
Add the arugula to the skillet and heat until the arugula starts to wilt, about 2 minutes.
Divide the bean mixture evenly atop the prepared crostini.
Top with the pomegranate arils.