Heat the oven to 220 C / 425 F with racks in the upper and lower thirds. Cut the sweet potato into 2 cm cubes, the red onion into wedges, and the zucchini and pepper into 2.5 cm pieces.
Toss the vegetables and the dried chickpeas with the olive oil, cumin, smoked paprika, 1/2 tsp salt and the pepper. Divide between two 33 x 46 cm / 13 x 18 inch sheet pans in a single layer with space between the pieces. Roast for 30 minutes, tossing and swapping the pans between racks at 15 minutes, until the sweet potato is tender and the edges are browned.
Five minutes after the vegetables go in, combine the rinsed freekeh, water and 1/4 tsp salt in a 2-quart / 1.9 L saucepan. Bring to a boil, then cover, reduce to low, and simmer for 18 to 20 minutes until the water is absorbed and the grains are tender with a slight chew. Take off the heat, keep covered for 5 minutes, then fluff with a fork.
While everything cooks, whisk the tahini, lemon juice, 3 tbsp water, garlic, maple syrup and 1/4 tsp salt in a small bowl until smooth. Add more water a teaspoon at a time until it falls off a spoon in a slow ribbon. Toast the pumpkin seeds in a dry 20 cm / 8-inch skillet over medium heat for 2 to 3 minutes until they pop and smell nutty.
Divide the spinach and freekeh between four bowls. Top with the roasted vegetables and chickpeas, drizzle with the lemon tahini, and finish with the toasted pumpkin seeds and parsley.