Sesame Lamb 'Gyros'

4 each pita bread, slightly toasted or grilled

2 tablespoons Chinese sesame paste (or 2 tablespoons peanut butter mixed with 1 teaspoon sesame oil)

2 cups plain yogurt

1 lemon, juiced

1 tablespoon garlic, minced

1 cup cucumber, peeled, 1/16-inch dice

3 to 5 slices leftover cooked lamb per pita, slightly warmed on a grill or Sauteed in olive oil

2 large tomatoes, 1/4-inch slices and seasoned with salt and pepper

1 tablespoon toasted sesame seeds

Salt and black pepper, to taste