Preparation Purée watermelon, yogurt, ginger, salt, 1/3 cup sugar, and 1 tablespoon lime juice in a blender until smooth. Add more sugar and lime juice, if desired. (Purée will taste less sweet once frozen, so err on the sweet side.) Divide purée among ice-pop molds. Freeze until mixture begins to set around edges of molds, 45-60 minutes. Stir mixture in molds to blend; insert sticks. Freeze until solid, at least 4 hours. Dip molds briefly in hot water to release paletas. DO AHEAD: Paletas can be made 1 week ahead. Keep frozen.
Preparation Purée watermelon, yogurt, ginger, salt, 1/3 cup sugar, and 1 tablespoon lime juice in a blender until smooth. Add more sugar and lime juice, if desired. (Purée will taste less sweet once frozen, so err on the sweet side.) Divide purée among ice-pop molds. Freeze until mixture begins to set around edges of molds, 45-60 minutes. Stir mixture in molds to blend; insert sticks. Freeze until solid, at least 4 hours. Dip molds briefly in hot water to release paletas. DO AHEAD: Paletas can be made 1 week ahead. Keep frozen.