Combine peanut butter, hoisin sauce, white vinegar (or lime juice), milk, minced garlic, and crushed chili paste in a bowl.

Whisk or blend until smooth, adding a little more milk to reach desired dipping consistency. Taste and adjust seasoning (more vinegar for tang, more hoisin for sweetness, or more chili for heat).

Transfer to a serving bowl and top with crushed peanuts and fresh cilantro.

Use as a dip for rice-paper rolls, grilled meats, or vegetables. Store refrigerated and use within 2 days.