Combine barley and water in a saucepan and bring to a boil. Cover, reduce heat, and simmer until tender, about 1 to 1 1/2 hours. Cool completely.
Blend garlic, almonds, olive oil, lemon juice and zest and salt in a food processor or blender until smooth. If the mixture is very thick or dry, mix in 1-2 tablespoons of water.
Blanch sugar snap peas: Have ready a large bowl of ice water, a slotted spoon, and a plate lined with a cloth or paper towel. Bring a pan of water to boil over high heat. Add a tablespoon of salt and the snap peas and boil just until bright green and crisp, about 1 minute. Transfer immediately to the ice bath. When the peas are completely cool, remove them from the ice bath and drain on the towel-lined plate.
Assemble salad: In a large bowl, combine barley and garlic sauce. Then mix in snap peas and mint. Season to taste and serve immediately or keep covered in the refrigerator.