Begin by cooking the farfalle: Bring the water to a boil in a large pot. Add the kosher salt and the farfalle.
While the farfalle cooks, make the Basil Pesto: Heat a small skillet on low heat, and cook the pine nuts (both for the pesto and the garnishes) until toasted about five minutes.
Put a half of the pine nuts in a food processor, and process until finely chopped. Add the rest of the ingredients, except for the pasta water, and process until everything is minced and combined. Add the pasta water, and process until a creamy sauce is formed.
Drain the farfalle and pour it into a large bowl. Add the pesto and stir until combined. Also add in the tomatoes, arugula, feta, olives, and the rest of the pine nuts. Garnish the dish with the red onion and basil leaves.