Spicy Chicken Tikka Tacos

Name: Spicy Chicken Tikka Tacos
Cook time: 30 min
Total time: 30 min
Cuisine: Mexican, Latin American, American
Ingredients: 2 tbsp olive oil; 1 cup yellow onion, diced small ((or 1/2 medium onion)); 2 lbs ground chicken breast; 1 tsp kosher salt; 1/2 tsp black pepper; 1 tsp freshly grated ginger; 3 cloves garlic (minced); 1.5 tsp curry powder; 1/2 tsp cayenne pepper ((use 1/4 tsp. for mild, and omit if you don't like spice)); 1/4 tsp ground cinnamon; 1/2 tsp paprika; 1 tsp ground cumin; 1/2 tsp ground turmeric; 3 tbsp tomato paste; 1 [13.5-ounce] can unsweetened coconut milk; 8-10 flour tortillas (I like Siete Foods grain-free Cassava Tortillas (*see notes for Whole30 ideas)); 1 cup english cucumber, cut in half lengthwise and sliced thin; 1/4 cup fresh cilantro leaves; 1 small serrano pepper, very thinly sliced ((optional)); 1 cup baby arugula; 1 lime, cut into wedges