Beef Flatbread Tacos

I found this in Cooking Light's April 2015 issue.  The recipe indicates that it can be made with beef or lamb...or maybe a combination of the two.  I see this being very popular at my house in the summer time.

1 6oz. container plain 2% Greek yogurt
1 tbsp. olive oil
3/4 tsp. black pepper, divided
1/4 tsp. kosher salt, divided
4 multi grain flatbreads
1 English cucumber
12oz. 90% lean ground beef
1 14.5oz. can Italian style diced tomatoes

Preheat broiler to high.

Combine yogurt, olive oil, 1/4 tsp. pepper, and 1/8 tsp. salt.

Cut each flatbread in half at the fold.  Broil 1 minute or until toasted, turning after 30 seconds.

Cut cucumber in half lengthwise.  Place cut side down and cut into 1/4 inch slices.

Heat a non stick skillet over medium high heat.  Add ground beef to pan, stirring to crumble.  Add tomatoes to pan; cook 6 minutes.  Stir in remaining salt and pepper.

Spread 1 tbsp. yogurt mixture on each flatbread half; divide beef mixture between flatbreads.  Top with cucumber slices and additional yogurt if desired.