Wash each zucchini and pat dry. Slice in half lengthwise, or, leave whole. Lightly oil the zucchini's surface.
Place zucchini directly on the heated grill grates. Grill, turning from time to time, until softened and lightly charred. Grilling can be done on the stove top using a grill pan, or broiled in the oven, but, turn every so often so they cook evenly.(I used a stove top grill pan.)
Remove zucchini from heat and allow to cool. Slice off the top and the bottom off each zucchini and cut them into large chunks.
In a small mixing bowl combine tahini, cumin, salt, garlic, lemon juice, and olive oil until well-blended.
Place grilled zucchini chunks and tahini mixture in a blender or food processor and blend until smooth. Adjust seasonings, if necessary.
Transfer to a serving bowl and drizzle additional olive oil on the top.
Garnish with toasted pine nuts, additional ground cumin, chopped parsley, or za'atar, if desired.
Serve with an assortment of fresh vegetable sticks, pita bread triangles, pita chips, or crackers.