Add water and red pepper to a small bowl. Wrap with plastic wrap and cut a hole to let out steam. Microwave on high for 45 seconds or until liquid boils. Let cool fully. Strain mixture through a fine chinois, saving liquid and throwing away any solids.
Using a food process or blender, pulse garlic until finely chopped. Blend in sun-dried tomatoes until finely chopped. Spoon the mixture into a bowl and mix in red pepper water, cheese, walnuts, and diced tomatoes.