Make the first course grilled sturgeon with avocado salad and green-gazpacho sauce, a puree of zucchini, cucumber, and other vegetables.
In a medium bowl, combine olive oil, avocados, red onion, cilantro, and lemon juice. Season mixture with salt and pepper to taste; cover with plastic wrap and chill in refrigerator, up to 2 hours.
Oil the grill, and heat. Season fish with salt and pepper; grill until opaque and flaky, 5 to 7 minutes on one side only. Do not move the fish while it is grilling.
Divide avocado salad among 12 plates. Place a piece of fish on top of each salad. Drizzle with gazpacho sauce, and serve.