Mix the masarepa, water and salt in a bowl until well combined. Let stand for a few minutes until the mixture sticks together.
Separately, in another bowl, season ground lamb with all the spices.
Heat olive oil in a saute pan over medium high heat. Cook lamb until fully browned. Keep warm (covered) until ready to serve.
Form arepa patties about 3 to 4 inches across and 1/2 inch in thickness using hands.
Coat a saute pan with olive oil and cook arepas until brown (or charred, depending on preference) on both sides. Both sides should be crispy.
Allow to cool and then slice the arepa lengthwise without cutting all the way through.
Spread hummus on the top and bottom flap of the arepa. Add the spiced lamb mixture and top with diced tomato, diced pepper (if using) pine nuts and mint. Serve immediately or room temperature.