Prepare chickpeas in instant pot
Rice: Bring 1 ¾ cups water to a boil. Add the rice, garlic powder, and salt. Stir once, then cover and simmer 10 to 15 minutes. Once all the liquid has cooked out and the rice is tender, remove the heat. Cover the pot and allow the rice to steam for 5 minutes.
Tzatziki: Meanwhile, grate ½ the cucumber using the small holes on a box grater (if using a standard cucumber, peel and seed it first). Place the grated cucumber in a fine mesh strainer and squeeze out as much liquid as possible. Sprinkle it with ¼ teaspoon kosher salt, then place over a liquid measuring cup and allow to stand for at least 10 minutes. In a medium bowl, mix the yogurt, garlic, red wine vinegar, olive oil, remaining ½ teaspoon kosher salt, dill, and freshly ground black pepper. Squeeze out more water from the cucumber before adding it to the dip. Stir in the grated cucumber. Depending on your yogurt consistency, you can stir back in the cucumber water (or regular water) until it comes to the desired consistency (some Greek yogurts are very thick!). Stores up to 1 week in the refrigerator.
Chickpeas: In a medium bowl, mix chickpeas with the spices and kosher salt. Heat the olive oil in a medium skillet. Add the chickpeas (carefully to avoid spitting) and cook for about 5 minutes, stirring often, until warmed through.
Chop cucumber, red onion, and tomatoes.
Add the rice to a bowl and top with the vegetables and chickpeas, then sprinkle with olives and feta crumbles and add a dollop of tzatziki. Leftovers last up to 3 days refrigerated.
