Position racks in the top and bottom third of the oven and preheat the oven to 450°F (220˚C). Line two half-sheet pans with parchment paper.
Cut the zucchini in half lengthwise and score the cut sides with a crosshatch pattern to create more surface for the salt to penetrate and later for the sauce to seep into. Sprinkle the cut sides with salt and let it sit for 10 minutes.
Meanwhile, prepare the crispy chickpeas: Place the chickpeas into a bowl and pat them dry with a clean kitchen towel or paper towels. Add the potato starch, garlic powder, salt, sesame seeds, and pepper and toss with your hands or a wooden spoon to coat them evenly. Drizzle on the olive oil and sesame oil and toss to coat again. Pour the chickpeas onto one of the lined sheet pans and roast on the upper rack for 20 to 25 minutes, until golden and crispy.
To make the huli huli sauce: In a bowl, whisk together the ketchup, soy sauce, brown sugar, vinegar, ginger, and grated garlic. Set aside.
To finish: In a large skillet, heat the neutral oil over medium-high heat until shiny. Pat the zucchini dry with paper towels, then place them cut-side down and cook untouched for 5 minutes.
Carefully transfer the zucchini to the remaining prepared sheet pan, cut-side down, and brush the huli huli sauce all over the skin side. Roast on the lower rack for 5 minutes. Flip the zucchini over, brush with more huli huli sauce, and roast for another 5 minutes cut-side up. (By now the chickpeas should be ready to come out of the oven.) Take the chickpeas out and turn on your broiler. Brush more sauce onto the cut side of the zucchini, put the zucchini: on the upper rack, and broil on high for 1 to 2 minutes, until caramelized.
To serve, place the zucchini on a plate, cut-side up, sprinkle on the crispy chickpeas, and garnish with the green onions.