English (aka hothouse) cucumbers will be the easiest variety to find for this herby, lemony salad, but they're less flavorful than long, slender varieties such as Armenian and Japanese. Read more about cucumbers in the Wall Street Journal's "Off Duty" section.
Thinly slice the cucumber lengthwise into ribbons using a mandoline or vegetable peeler and place in a bowl.
In a food processor, pulse the parsley, dill, tarragon, garlic, red pepper, and lemon zest together until finely chopped. With the machine running, slowly pour in the lemon juice and oil, scraping down the side of the bowl as needed, until smooth. Season to taste with salt and pepper.
Gently toss the cucumber with the pesto and divide among plates. Finely grate some lemon zest over each salad and sprinkle with pine nuts, if using. With a vegetable peeler, shave some cheese over each salad and serve.