Heat grill to medium-high heat or medium-hot coals.
Swordfish. In a medium-size bowl, combine lime juice, mint, 1/4 cup water, sugar and lime zest. Whisk in oil, salt and pepper until blended. Pour 1/3 cup of the marinade into a resealable plastic bag and add fish. Marinate in the refrigerator for 15 minutes.
Meanwhile, prepare Avocado Chopped Salad. Gently stir together avocados, celery, red onion and 1/3 cup of the remaining dressing.
Remove fish from bag (discard marinade) and grill 6 to 8 minutes, depending on thickness, turning once. Transfer fish to a platter and drizzle with remaining dressing. Serve with Avocado Chopped Salad.