1. Heat a large nonstick skillet over medium-high heat. Add 1 tablespoon oil; swirl to coat. Sprinkle fish evenly with 1/4 teaspoon salt and 1/4 teaspoon pepper. Add fish to pan; cook 3 minutes on each side or until fish flakes easily when tested with a fork.
2. Combine remaining 1/4 teaspoon salt, remaining 1/4 teaspoon pepper, remaining 2 tablespoons oil, mint, juice, and syrup in a large bowl, stirring with a whisk. Add spinach, peaches, and cucumber; toss gently to coat. Divide spinach mixture among 4 plates; top with fish. Sprinkle with almonds.