Make the hummus:
Process chickpeas, tahini, oil, lemon juice, salt, and garlic in a food processor until a coarse paste forms, about 20 seconds, stopping to scrape down sides as needed. With processor running, slowly pour 1/4 cup reserved chickpea liquid through food chute, process until mostly smooth and creamy, about 1 minute and 30 seconds. (If desired, add more chickpea liquid for looser hummus.) Add salt to taste.
Make the chicken and cauliflower:
Toss together chicken, cumin, paprika, salt, coriander, cinnamon, and pepper in a medium bowl until chicken is well coated. Heat 2 tablespoons oil in a 10-inch high-sided skillet over medium-high. Add chicken in an even layer; cook, undisturbed, until bottom of chicken is lightly browned, about 5 minutes. Stir and cook, stirring occasionally, until chicken is cooked through, about 4 minutes; transfer to a medium bowl. Reduce heat to medium. Add onion and remaining 2 tablespoons oil; cook, stirring occasionally with a wooden spoon to loosen browned bits, until softened and lightly browned, about 15 minutes. Stir in cauliflower, 1/3 cup water, and currants; cover and cook, stirring occasionally to loosen onions from bottom of pan, until cauliflower is tender and onions are caramelized, about 10 minutes. Return chicken to pan, and cook until warmed through. Season with salt to taste.
Spread hummus on a large serving platter, making a well in the hummus with the back of a spoon. (Alternately, divide hummus among individual serving plates, and make a well in each.)Spoon the chicken and cauliflower mixture into the well (or individual wells). Garnish with parsley, za’atar, and pine nuts. Drizzle with oil. Serve immediately.