Combine chicken, tequila and limejuice in small shallow dish.
Cover and marinate at least 30 minutes and up to 2 hours, turning occasionally.
Prepare barbecue (medium-high heat) or preheat broiler.
Drain chicken; reserve marinade; season chicken with salt and pepper.
Grill or broil until just cooked through, occasionally basting chicken with some reserved marinade, about 4 minutes per side.
Boil remaining marinade in small saucepan 1 minute.
Cut each chicken breast crosswise into thin slices.
Arrange slices on platter.
Garnish with lime wedges.
Serve, passing marinade separately as sauce.
Ready in 1 hour.