Shrimp Boil with Sausage and Spinach

Place potatoes on plate and microwave on High 2 min. Turn and microwave until just tender, 1 to 2 minutes more. Cut in half. Meanwhile, heat oil in large nonstick skillet on medium. Add onion and 1/2 teaspoon each salt and pepper and cook, stirring occasionally, until onion is tender, 4 to 6 minutes. Add potatoes and cook, stirring occasionally, until light golden brown, 2 to 3 minutes. Push to one side of pan. Add kielbasa to other side of pan and cook, stirring occasionally, until starting to brown, 3 to 4 minutes. Add garlic, coriander, mustard and cayenne and cook, tossing, 1 minute.  Add shrimp, corn and spinach; cover and cook, shaking pan occasionally, until shrimp are opaque throughout, 2 to 3 minutes.