Cook turkey patties for 2 minutes. Turn patties over. Cook until internal temperature reaches 165 F, 2 to 3 minutes.
Whisk prepared tzatziki and Sriracha until well blended.
Spread 2 Tbsp Sriracha-Tzatziki Sauce on top half of roll (toasted if desired).
Layer the following on bottom half of roll: lettuce leaf, tomato slice, onion slice, 3 cucumber slices, cooked turkey patty, 1 Tbsp feta, top half of roll.