Cook tilapia in microwave or oven according to package instructions.
Meanwhile, to make sundried tomato sauce, combine vinegar, 1/4 cup (60 mL) olive oil, sundried tomatoes, 2 cloves garlic, Thai chili, 1/4 tsp (1 mL) salt and pepper in small saucepan. Bring to rapid simmer over medium-high heat. Remove from heat; cool 10 min. Transfer mixture to food processor and pulse until smooth. Set aside.
Heat remaining 1 tbsp (15 mL) oil in large saucepan over medium heat. Stir in onion and remaining 2 cloves garlic; cook 3 to 4 min., or until softened. Mix in coriander, cumin, remaining 1/2 tsp (2 mL) salt, spinach and 1/4 cup (60 mL) water. Cook 1 to 2 min., until spinach is wilted.
Serve fish on a bed of spinach drizzled with sundried tomato sauce.