Ingredients:

• 2 ripe avocados
• 1/4 teaspoon kosher salt, plus more to taste
• 1 tablespoon fresh lime or lemon juice
• 2 to 4 tablespoons minced red onion or thinly sliced green onion
• 1 to 2 serrano (or jalapeño) chilis, stems and seeds removed, minced
• 2 tablespoons cilantro (leaves and tender stems), finely chopped
• Pinch freshly ground black pepper
• 1/2 ripe tomato, chopped (optional)
• Red radish or jicama slices for garnish (optional)
• Tortilla chips, to serve