For better facial skin, should i wash with water only or use a face wash with ingredients like salicylic acid?

Water's fine: Warm water and if dirty, mild soap is all you usually need. Salicylic acid and its derivatives are keratolytics (agents which cut through skin cells and can thin the skin, reduce the size of calluses and the like). Skin normally sheds on its own--half of household dust is human skin!

Oily skin?: If you have oily skin or are prone to blackheads or large pores salicylic acid is approriate. If however you have dry sensitive skin salicylic acid may be irritating, .

If you're oily: If you have oily skin, salicylic acid is great. It's a beta hydroxy acid that breaks apart dead skin cells and penetrates oil very well. For normal skin or as a daily wash it can be harsh and irritating. You can even develop an allergy to salicylic acid as it is a medication.