Heat the grapeseed oil in a large pot over medium heat, then add the diced onion and cook, stirring occasionally, until softened and beginning to brown, about 2–3 minutes.
Add the minced garlic, minced ginger, and Thai red curry paste to the pot and cook, stirring, until fragrant and evenly combined, about 1 minute.
Pour in the coconut milk, scrape any browned bits from the bottom of the pot, and stir to combine.
Add the cubed zucchini, cover the pot, and cook for 5 minutes; then remove the lid and stir.
Stir in the drained chickpeas and the sugar, bring the curry to a gentle simmer, then top with the baby spinach and replace the lid for 2 minutes.
Remove the lid, stir the spinach into the curry, then add the soy sauce, chopped cilantro, and chopped chives and stir to combine.
Taste and adjust seasoning if needed, then serve.