In a large bowl whisk together 1/2 cup olive oil, vinegar, lime juice, lime
peel, mint, parsley, garlic and ginger. Add the shrimp and scallops and stir
to coat. Cover and refrigerate for 2 to 3 hours. If using bamboo skewers, soak
them in hot water to cover for 30 minutes. Prepare a charcoal grill.
Drain shrimp and scallops, reserving the marinade. Place the seafood on
the skewers, alternating with the peppers, tomatoes, mushrooms and onion pieces.
Brush with the remaining 1/4 cup oil. Place on a hot grill and grill 3 to 5
minutes, until done, turning frequently and brushing with the reserved marinade.