Step 1
Place a rack in middle of oven and preheat to 350°. Heat ⅓ cup extra-virgin olive oil in a large Dutch oven or other heavy ovenproof pot over medium. Add 12 garlic cloves, thinly sliced, and cook, stirring often, until softened and fragrant, 2–3 minutes. Add one 14-oz. jar pitted green olives, drained, coarsely chopped (about 1 cup), one 3.5-oz. jar capers, rinsed (about ½ cup), and ¼ tsp. crushed red pepper flakes and cook, stirring occasionally, just until fragrant, about 2 minutes.
Step 2
Add 12 oz. orzo and one 6-oz. can tomato paste to pot and cook, stirring often, until tomato paste coats orzo and is darkened in color, about 4 minutes. Add one 15.5-oz. can chickpeas, rinsed, 1 tsp. dried oregano, 1 tsp. sugar, 1½ tsp. Diamond Crystal or ¾ tsp. Morton kosher salt, and 4⅓ cups water, stirring to scrape up any browned bits stuck to bottom of pot.
Step 3
Cover pot, transfer to oven, and bake until orzo is tender and about 80% of liquid has been absorbed, 30–35 minutes (having some liquid on top is okay as the orzo will continue to absorb it). Remove pot from oven, remove lid, and stir in 2 oz. Parmesan, finely grated (about 1 cup). Taste orzo and season with more salt if needed and freshly ground black pepper.
Step 4
To serve, divide orzo evenly among shallow bowls. Top each bowl of orzo with more Parmesan if desired, then season with a little more black pepper.