Heat oil in a large nonstick skillet over medium heat. Add onion; cook, stirring often, until aromatic and translucent, about 8 minutes. Stir in garlic; cook, stirring often, until aromatic, about 1 minute.
Stir in orzo and sun-dried tomatoes; cook, stirring often, until the orzo is toasted, about 1 minute. Add broth, beans, lemon juice, salt and oregano; bring to a boil over medium-high heat. Reduce heat to medium-low, cover, and simmer until the orzo is al dente, about 15 minutes.
Stir in spinach. Cook, uncovered and stirring often, until the spinach is wilted, about 1 minute. Remove from heat; top with feta, basil, pine nuts and lemon zest.
