Vietnamese Steak Wraps

Ingredients

• 1 1/2 lbs flank steaks
• 2 lemons, juice and rind of
• 6 tablespoons sugar, divided
• 2 tablespoons dark sesame oil
• 1 1/4 teaspoons salt, divided
• 1/2 teaspoon black pepper
• 1/4 cup water
• 1/4 cup rice vinegar
• 1/2 teaspoon crushed red pepper flakes
• 6 (8 inch) flour tortillas
• 6 lettuce leaves
• 1 small red onion, halved and thinly sliced
• 1/3 cup fresh mint leaves
• 1/3 cup fresh cilantro leaves