To make marinade, whisk together in medium bowl olive oil, orange zest, garlic, red onion, nutmeg, salt and pepper. Stir in Lager Beer. Transfer marinade to shallow glass dish; place tuna in marinade, turning to coat thoroughly. Cover and refrigerate at least 2 hours and up to 24 hours.
Preheat grill or broiler.
To make Orange-Avocado Relish, stir together in medium bowl the orange zest, orange section, avocado, tomato, Lager Beer, lime juice, garlic, red onion and nutmeg. Add sugar, salt and pepper, stirring well. Set aside until ready to serve.
Grill or broil tuna, turning, until cooked through, about 5 - 8 minutes per side for one-inch thick steaks. Serve with Orange-Avocado Relish on top of tuna steaks.
Nutritional Information, Per Serving:
425 calories; 18.4 g fat; 3.6 g saturated fat; 21.5 g carbohydrate