Step 1

In the bowl of a food processor, combine the beans, mascarpone, salt, and lemon zest, and process for 30 seconds, until pureed. With the machine running, add the lemon juice and olive oil, and continue to process until smooth, about another 30 seconds. Set aside.

Step 2

In a medium bowl, stir together the tuna, chopped celery stalks and leaves, sun-dried tomatoes, capers, parsley, olive oil, lemon juice, salt, and pepper.

Step 3

Spread 2 tablespoons of the white bean spread onto each English muffin half. Arrange a few arugula leaves on the spread and top with 2 tablespoons of the tuna salad and a drizzle of olive oil.