In a colander, toss the eggplant with 2 teaspoons of salt and let drain for 20 minutes. Rinse the eggplant well and squeeze out as much water as possible.
Heat 1/4 cup olive oil in a large saute pan. Add the eggplant to the pan and let cook over medium high heat until one side browns some. Do not stir. Next add the onions and lower the heat, stirring occasionally, until they have become soft but not browned, about 8 minutes. Add the garlic and cook for 2 minutes, stirring. Add half of the zucchini and cook until that too begin to soften, about 5 minutes. Stir in the tomatoes. Cover and cook over low heat, stirring occasionally, until the vegetables are very soft, about 10 minutes. Turn off the heat and set aside.
Bring 1 quart of water to a boil in a medium-sized stock pot add some salt along with the pasta pieces. Add the bouquet garni, cover and simmer gently over moderately low heat about 5-8 minutes and the pasta is al dente. Add the drained beans to the pot. Turn the heat off, add the reserved vegetables, stir to combine and cover the pot. Let it sit at least 20 minutes so that the flavors come together.
Remove the boquet garni and season the soup generously with salt and pepper taste. Stir in the remaining diced zucchini.
Put the almonds, basil, parsley, anchovies with some of their oil, and garlic in a food processor. Pulse 6 or 8 times until just combined. I prefer a varied texture so there is no need to scrape the sides. But you may if you like. Turn the machine on and add the remaining oil in a slow, steady stream. You might not need it all. Process until nearly smooth. Transfer the contents to a bowl. Stir in lemon zest; season with salt and pepper. Set aside 1/4 cup of this pistou for the prawns.
Heat a grill to medium-high. Toss the prawns with the reserved 1/4-cup of pistou. Grill, the prawns turning once, until cooked through, about 3 minutes per side; season with salt and pepper.
Just before serving, re-heat the pasta and beans. Spoon the reserved sauted vegetables onto a shallow sided serving bowl. Transfer the pasta and beans on top with enough of cooking water so that pasta and beans are brothy without being too soupy. Set the prawns on top with the remaining pistou. Garnish with lemon wedges and extra basil. Serve hot.