Whisk together the lime juice, cilantro, mint, cumin, jalapeños, salt, and pepper in a medium bowl until blended. Transfer half of the mixture to another medium bowl.
Place the meat in one bowl and the zucchini, onions, and tomatoes in the other bowl. Toss to coat and let stand at room temperature for about 10 minutes.
Preheat a grill or broiler to medium. Thread the meat and vegetables onto 4 metal skewers, distributing evenly. Brush with any remaining marinade.
Grill the kebabs for about 12 minutes (or broil for about 8 minutes), or until the meat reaches the desired doneness, turning often so that the meat and vegetables cook evenly. Arrange on a platter and serve.