Prepare your meat and vegetables by cleaning, seeding, cubing and chopping. Thread a piece of green pepper onto the skewer. Follow it with a cube of beef, then one half of a preserved lemon, a couple of pieces of red onion, another piece of beef, a piece of red pepper and top it with a mushroom. Repeat the process with the rest of the skewers. Set all of the kabobs into a roasting pan in one layer and set aside.
Place the remaining ingredients in a medium sized bowl and whisk until well mixed. Pour the mixture over the kabobs and refrigerate 1 hour.
Preheat an outdoor charcoal or gas grill to high heat. Place the kabobs on the grill and cook about 3 minutes per side. Remove and serve immediately or let cool, and take them on a picnic.
Serve with Cucumber-Yogurt Sauce.
Cucumber Yogurt Sauce:
Combine all ingredients in a food processor and pulse a couple of times to make a chunky sauce.