Combine cilantro, garlic, serrano chile, lime juice, water, salt, pepper, and sugar in a tall cup or the jar of a blender; blend with a stick blender or regular blender until smooth. Refrigerate aguachile while other ingredients are prepared.
Add shrimp, cucumber, and red onion to a bowl, and pour in aguachile. Stir well, and press shrimp down into aguachile to cover. Wrap and refrigerate for 30 minutes to 1 hour before serving.
Sprinkle aguachile with jalapeno slices and cilantro to garnish, and serve with tortilla chips.