Heat oil on medium-low heat in a skillet. Gently cook the onions until translucent, about 4 minutes.
Add the lamb and break up into fine pieces. Continue stirring until meat is browned. Add garlic and spices, mix well and stir until fragrant, about 1 minute. Stir in tomato sauce, cover, reduce heat to low and simmer for 15 – 20 minutes.
In the meantime heat oven for prepackaged corn taco shells and follow package instructions.
Serve picadillo in shells with sour cream, avocado and olives on top of each taco.
Zinfandelic Lodi Zinfandel