In a large skillet, heat oil over medium heat. Add the onion, bell pepper, chiles, and garlic. Saute until a little soft and translucent.
Add the ground lamb or beef and cook until browned.
Add the water and spices to the beef and let simmer until water has evaporated and the meat is well seasoned. Taste test and adjust spices as necessary. This would be an opportunity to add more chiles if you want more of a kick.
Roll out the puff pastry dough over a little bit of flour and cut into twelve squares. Fill each square one by one with the lamb or beef. Wet the edges of each square, add a spoonful of meat, then fold over into a triangle. Seal closed by pressing a fork around the edges. Continue until all squares have been used.
Heat a large pot of canola or sunflower oil over medium-high heat until it reaches 350 degrees. Work in batches so as to not crowd the pot and remove samoosas to paper towel lined plate when golden brown.
To make the avocado puree, blend together the avocado, lemon juice, salt and pepper until smooth. A stick blender or food processor will work well.
Serve hot with avocado puree on the side.