Preheat oven to 350 degrees. Line a 12 cup muffin pan with paper liners.
In a large saucepan over medium heat, warm the butter, brown sugar, and rhubarb. Once it comes to a slow simmer, remove from heat and let cool.
Once rhubarb mixture has cooled, whisk in eggs. In a medium bowl, combine flour, baking powder, cinnamon, salt and lime zest. Add flour mixture to rhubarb mixture, stirring to combine. Stir in lime juice.
Divide batter evenly between prepared muffin cups.
For topping: in a small bowl, stir together melted butter, flour, brown sugar, almonds, cinnamon, and salt with a fork until crumbly. Sprinkle topping over batter filled cups, pressing topping into batter.
Bake until a wooden pick inserted in center comes out clean, about 20 minutes. Let cool in pan 5 minutes. Remove from pan and cool completely on a wire rack.
To make the glaze: In a small bowl, whisk confectioners sugar and lime juice together until smooth. Drizzle over muffins.