Put the olive oil in a medium pot over medium-high heat. When it’s hot, add the leek and season with salt and pepper. Cook, stirring occasionally, until it softens, 8 to 10 minutes.
Add the quinoa and stir until it dries out and begins to stick together, about 5 minutes. Add the tomatoes, the chickpeas, and 3 cups of water. Raise the heat to high and bring to a boil, then cover the pot and adjust the heat so the mixture simmers gently. Cook until the quinoa has absorbed all the liquid and is tender, 15 to 20 minutes.
Remove the pot from the heat and let sit for 5 minutes. Stir in the feta and dill, then taste and adjust the seasoning. Serve hot, warm, or at room temperature. (Store leftover quinoa pilaf in an airtight container in the refrigerator for up to several days.)
