Heat olive oil, garlic, and lemon zest in a large skillet on medium until beginning to brown, about 1 min.
Add salsa and tomato sauce and bring to a simmer. Nestle shrimp in the salsa mixture and cook, covered, 3 min.
Fold in spinach and cook until beginning to wilt and shrimp are opaque throughout, 1 to 2 min. more.
Sprinkle with feta and serve with flatbread if desired.
Nutrition per serving:
121 cal, 8 g pro, 9 g carb, 3 g fiber, 4.5 sugars (0 g added sugars), 6 g fat (2 g sat fat), 52 mg chol, 966 mg sodium