In a bowl, combine yogurt, cucumbers, garlic and juice. Set aside

In another bowl, mix beef, zucchini, feta, onion, marjoram, salt and pepper.

Form beef mixture into four 3/4 inch thick patties.

Coat a grill pan or grill rack with cooking spray.

Grill patties over medium-high heat, flipping once, about 5 minutes each side, until internal temperature reaches 160.

Divide roasted peppers evenly among bottom roll halves

Top with 1 burger, 1/4 yogurt sauce and lettuce and cucumber, if desired.

Top each with other half of roll.