Cook rice according to package directions. Meanwhile mix avocado with lime juice, cumin and half the salt and half the cilantro or parsley. Stir into rice.
Meanwhile, preheat grill to high, grease grate well. Toss shrimp with oil, garlic, lime zest and remaining salt. Thread evenly onto metal or soaked wooden skewers. Grill skewers, for 2 to 3 minutes per side or until shrimp start to curl and turn pink.
Serve rice with shrimp skewers. Garnish with remaining cilantro or parsley.