Cook sausage over medium-high heat, stirring frequently, until thoroughly cooked and no longer pink. Remove from heat and allow to cool in pan. Stir in onion, cilantro and cheese. Place 20 wontons on a flat surface. Stir egg yolk and cream together in a small bowl; brush all 20 wontons with egg wash. Place 1 tablespoon of the filling in the center of each wrapper; fold wonton over to form a triangle. Seal edges with fingers or crimp with fork. Brush tops with egg wash. To cook: In a wok, Dutch oven or fryer, add oil to a depth of 3 inches; heat to 375° F. Fry 3 or 4 at a time about 3 minutes or until deep golden brown; drain on paper towels. Or place on greased cookie sheet and bake at 400° F. for 20 minutes or until browned on each side, turning each wonton over after 10 minutes. Serve with guacamole, sour cream and/or salsa. Note: Freeze Sausage Wontons on cookie sheet and place in resealable bag until ready to cook.