Season cauliflower with 2 tablespoons olive oil, 1/2 teaspoon salt, and 1/4 teaspoon pepper in a bowl.
Combine white wine, dried cranberries, and honey in a heat-proof bowl and cover with aluminum foil.
Turn on a multi-functional pressure cooker (such as Instant Pot(R)) and select Saute function. Heat 1 tablespoon oil; stir in farro with 1 teaspoon salt and cook until glossy, about 3 minutes.
Pour water over farro and place steamer rack on top. Place cauliflower florets and bowl with cranberries mixture on the steamer rack. Close and lock the lid. Select high pressure according to manufacturer's instructions; set timer for 8 minutes. Allow 10 to 15 minutes for pressure to build.
Release pressure using the natural-release method according to manufacturer's instructions, 10 to 40 minutes. Unlock and remove lid. Remove cauliflower, bowl of cranberries, and strain farro.
Mix 1 tablespoon of cooking juice from the cranberries with 1/4 cup olive oil, lemon juice, 1/2 teaspoon salt, garlic, and 1/4 teaspoon pepper in a bowl to make the dressing.
Chop cauliflower into bite-size pieces and sprinkle on top of farro in a bowl. Toss in cranberries and pistachios; drizzle generously with dressing.