Lightly salt and pepper the shrimp. Heat up 1 tablespoon oil in the same pan used for the scallions, and add the shrimp in batches. Cook for approximately 2 minutes per side. They won't be completely cooked through. When they're added to the sauce, they'll finish cooking.
Pour the wine into a medium pot over medium-high heat, and bring to a simmer. Simmer for 10 minutes to reduce the wine to about 3/4 cup. Add the clams all at once, and cover the pot. Cook until the clams all open, about 10 minutes. Remove from the broth, and reserve the broth for later.
Add 3 tablespoons oil to a large heavy-bottomed pot - I use my Le Creuset with great success - over medium-high heat. Stir in the garlic paste and cook for 1 minute. Add the cauliflower and red pepper chunks all at once and toss to completely coat with oil and garlic. Sauté until fragrant and slightly soft, about 10 minutes. Add the raisins and cook for an additional 2 minutes, tossing often. There should be a brown coating on the bottom of the pot by now. Add the balsamic vinegar, toss, and scrape up the brown bits from the pot.
Stir in the tomatoes, and squeeze the tomatoes by hand to tear into pieces. Add the vegetable broth, 1/2 cup of the reserved clam and wine broth, salt, and harissa.
Grind the oregano, fennel, and orange peel together using a mortar and pestle. Add to the sauce. Stir in the chickpeas and bring to a simmer. Simmer for 10 minutes to blend the flavors, and add the chunks of feta, cooked shrimp, and cooked clams. Cook for another 5 minutes to slightly melt the feta and warm up the seafood. The shrimp will finish cooking at this stage.
To serve, spoon 1/2 cup cooked Israeli coucous on a plate and top with a generous serving of the sauce. Finish with the garnish of cooked scallions.