Margarita Poke Cake

Name: Margarita Poke Cake
Ingredients: All-purpose flour, for dusting; 1 box vanilla cake mix, plus ingredients called for on box; 1 14-oz. can sweetened condensed milk; 1/2 c. heavy cream; 1/3 c. freshly squeezed lime juice; 1 tbsp. grated lime zest; 1 tbsp. tequila; 2 drops of green food coloring (optional); 1 c. butter, softened; 5 c. powdered sugar; 1/4 c. lime juice; 1/4 c. tequila; Coarse salt, for garnish; Limes, cut into half moons, for garnish; Lime zest, for garnish; cocktail umbrellas, for garnish