Cut squash in half lengthwise; remove seeds. In 8-inch square (2-quart) glass baking dish, place squash halves, cut side down. Cover with microwavable plastic wrap. Microwave on High 9 to 11 minutes or until squash is fork-tender.
Meanwhile, in 2-quart saucepan, heat peas, water, thyme and salt to boiling over high heat. Stir in rice; return to boiling. Reduce heat to low; cover and simmer 5 minutes. Remove from heat; stir. Let stand covered 5 minutes or until liquid is absorbed.
Heat 8-inch nonstick skillet over medium heat. Add sausage patties; cook 5 to 6 minutes or until lightly browned and thoroughly heated, breaking up patties into 1/2-inch pieces as they thaw.
Fluff rice mixture with fork; stir in sausage and cheese. Spoon rice mixture into squash halves.