Thaw shrimp in the refrigerator overnight, remove from refrigerator, pat dry with paper towels, and season with kosher salt and black pepper in a medium-sized bowl; set aside.
Add coconut and sesame oils to a large-sized saucepan and bring to medium-high heat.
Add pepper, onion, and garlic and sauté for about 45 seconds.
Add mushrooms and pinch of salt and pepper and sauté until tender, about 90 seconds.
Add sriracha and soy sauce and sauté for another 30 seconds.
Add coconut milk, stock, and almond butter, bring to a boil, whisk until fully incorporated, then reduce to medium heat and cook for about 2 minutes, until slightly thickened.
Add seasoned shrimp to pan and continue to cook until fully cooked with a sauce-like consistency; about 4 to 5 minutes.
Season to taste with salt and pepper and finish by stirring in chopped cilantro.
Serve hot with tuna steaks and brown rice.